01How cities came to need infrastructure

The short version: Every system in a modern city began as an answer to a specific problem: too little clean water, too much waste, fire, darkness, distance, traffic, pollution, and now rising seas. The answers piled up in layers over about 5,000 years, from brick drains in the Indus Valley to court-ordered sewage plants and flood barriers. Most of the pipes, wires and rules under a city street today date from the 1850s onward, and most were built after something went visibly wrong. Boston, the worked example in this guide, shows up at almost every step.

What did the first cities build?

Cities and infrastructure grew up together. Uruk, in southern Mesopotamia (present-day Iraq), had up to 50,000 residents at its peak around 3100 BC, with another 80,000 to 90,000 people in the surrounding area, which probably made it the largest urban area in the world at the time.⁴ The earliest known examples of writing come from its Eanna district.⁴ Around 3000 BC, Uruk built a city wall about 9 km (5.6 miles) long.⁴

The clearest early evidence of urban plumbing comes from the Indus Valley. Mohenjo-daro, in present-day Pakistan, was built in the 3rd millennium BC and flourished between about 2500 and 1500 BC.⁵ Its streets cross at right angles, with a citadel to the west and a lower town to the east, and it had what UNESCO calls "an elaborate drainage system," along with wells and soak pits for sewage.⁵

The street drains were built of baked brick set in mud mortar and covered with flat bricks or limestone blocks.⁶ Vertical pipes inside house walls carried wastewater down to chutes that emptied into the street drains, and settling pools along the way caught sediment and were cleaned out from time to time.⁶ Mohenjo-daro became a UNESCO World Heritage Site in 1980.⁵

Rome added water at a scale no earlier city had managed. Its great drain, the Cloaca Maxima, is traditionally dated to about 600 BC and credited to King Tarquinius Priscus.⁷ It was built to drain marshes and carry away waste, began as an open channel, and was covered over gradually; parts of it still carry rainwater in central Rome today.⁷ Rome's first aqueduct, a channel that carries water by gravity from a distant source, was the Aqua Appia, commissioned in 312 BC by the censor Appius Claudius Caecus.⁸

By the late 3rd century AD, 11 aqueducts served the city, with a combined length of about 780 to 800 km (485 to 500 miles).⁸ Only about 47 km (29 miles) of that ran above ground.⁸ The famous arches were the exception; most of the system was a buried, sloping channel.

Rome also produced one of the first infrastructure reports. Frontinus became the city's water commissioner (curator aquarum) in 97 AD and wrote De aquaeductu, an official account of the supply.⁸ Modern estimates based on his figures put the city's daily supply anywhere from about 520,000 to 635,000 cubic meters up to 1,000,000 cubic meters.⁸

The pattern these cities set has lasted ever since: bring clean water in by gravity, carry dirty water away by gravity, and lay out streets so both are possible.

Why were old cities so afraid of fire?

For roughly 1,500 years after Rome, most European cities drew water from wells, rivers and conduits, and human waste went into a cesspit, a pit beneath or beside a building where it collected until someone emptied it. In Tudor England, the people who did that work were called gong farmers. They were allowed to work only between 9 pm and 5 am, which is why they were also called "nightmen."⁹

The waste, known as night soil, was carted out of town.⁹ In London, much of it went to riverside wharves such as Dung Wharf and was shipped by barge to farms and market gardens.⁹ In effect, this was a recycling system. It began to come apart once flushing toilets sent waste into sewers and rivers instead of into pits.

Japan offers a non-European example. In the Edo period (1603-1868), local systems for circulating organic material formed between the early modern cities and the villages around them, and the use of night soil as fertilizer was especially common in the suburbs of Osaka and Edo (now Tokyo).¹⁰ Edo also organized against fire: the Kyōhō Reforms of 1720 created the machi bikeshi, town fire brigades made up of commoners appointed by town officials, which in time came to be seen as a competent force and helped samurai brigades fight the 1747 Edo Castle fire.¹¹

The bigger fear was fire. The Great Fire of London began on Sunday, September 2, 1666, in Thomas Farriner's bakery on Pudding Lane, and was mostly under control by September 5.¹² It destroyed 13,200 houses, 87 parish churches, St Paul's Cathedral, the Royal Exchange and the Guildhall, with damage estimated at £10 million.¹² (The recorded death toll is low and widely disputed, so we do not give a figure here.)

Two lasting city systems came out of the ashes. The first was organized firefighting: after the fire, insurance businesses hired men to fight fires, forming the first fire brigades.¹² The second was the building code, legal rules for how buildings must be built. The Rebuilding of London Act 1666, which received royal assent on February 8, 1667, favored brick and stone; regulated wall thickness, street widths and house heights; and banned jetties, the overhanging upper floors that let fire leap across narrow lanes.¹³ It was paid for with a duty on coal.¹³ Rebuilding under Christopher Wren's plans took more than 30 years, and the Monument to the fire, 202 feet (62 m) tall, went up in 1671-1677.¹²

Private insurers moved first, and governments followed with rules for everyone.

How did cholera build the modern sewer?

Industrial cities in the 1800s grew faster than their wells and cesspits could cope with. Cholera made the problem impossible to ignore. Britain's first cholera epidemic, which ran to 1832, killed about 30,000 people.¹⁴ The older explanation, miasma, held that disease spread through foul-smelling "bad air."

In 1854 a London doctor, John Snow, tested a different idea. An outbreak began in Soho on August 31, 1854, and about 500 people died within 10 days.¹⁴ Snow mapped where the victims lived and found the deaths clustered around a single public water pump on Broad Street.¹⁴ The pump's handle was removed, and a leaking sewer was later found to have contaminated the well.¹⁴ His theory that cholera spread through water was not accepted at first.¹⁴ Acceptance came after an 1866 outbreak in East London struck areas not yet connected to the city's new sewers.¹⁴

Those sewers had been prompted by smell rather than by Snow. In the hot summer of 1858, the Thames stank so badly that the episode became known as the "Great Stink."¹⁵ Joseph Bazalgette, chief engineer of the Metropolitan Board of Works, then built six intercepting sewers, large pipes that catch the flow of many smaller sewers before it reaches the river and carry it elsewhere.¹⁵ They totaled about 100 miles (160 km), fed by about 450 miles (725 km) of main sewers, and used 318 million bricks and Portland cement, with pumping stations at Abbey Mills, Deptford and Chelsea, among others.¹⁵ The work cost about £3 million at the time.¹⁵

The fix arrived before the science was settled. Bazalgette's sewers were designed partly to get rid of bad smells, and they cut cholera anyway, because they also kept sewage out of drinking water.

Paris rebuilt on an even larger scale. Napoleon III made Haussmann prefect of the Seine in 1853, with a mandate to "aerate, unify and beautify" the city; Haussmann was dismissed in January 1870.¹⁶ His program demolished 19,730 buildings containing about 120,000 homes and built 34,000 new buildings with about 215,300 apartments.¹⁶ Paris had 142 km (88 miles) of sewers in 1852, and the network grew about fourfold by 1869, while the engineer Eugène Belgrand's new aqueducts nearly doubled the water available per person.¹⁶ The program also created four major parks and 24 new squares.¹⁶

Historians still argue about it: critics have said the wide new boulevards were meant partly to make uprisings easier to put down, and defenders call that a secondary motive. How much rents rose and how many working Parisians were pushed out are also disputed.

Chicago had a different problem: it was too flat to drain. Ellis Chesbrough left Boston in 1855 to become engineer of Chicago's Board of Sewerage Commissioners, at a time when Chicago had the highest death rate of any US city.¹⁷ Because the ground was too low for sewers to flow, he had downtown raised about 10 feet (3 m), with buildings lifted on jackscrews.¹⁷ He also built a water tunnel two miles (3.2 km) out under Lake Michigan to an offshore intake, called a crib.¹⁷

In January 1900, gates at Lockport opened on the 28-mile (45 km) Sanitary and Ship Canal, and the Chicago River reversed direction, carrying sewage away from the lake.¹⁸ Chicago did not build sewage treatment plants until the 1920s.¹⁸ (One widely repeated story, that disease killed about 12 percent of Chicagoans in 1885, is a documented myth: mortality records show no cholera deaths that year, and the Chicago Tribune retracted the claim in 2005.¹⁹)

In London and Chicago alike, the first solution was to move waste somewhere else: farther down the Thames, or down the Illinois River. Treating it came decades later.

In Boston: making land and fighting fire

Boston's version of the sanitary story starts with a dam. A milldam closing off the tidal Back Bay was chartered in 1814; it cut off the tide's daily flushing and left a stagnant, polluted basin behind it.²⁰ Boston's answer was to fill the bay in. Filling began in 1857, and Back Bay itself was filled by 1882, with the work reaching Kenmore Square by 1890 and the Fens by 1900.²⁰ The gravel came by rail from Needham, about 9 miles (14.5 km) away, with a 35-car train arriving every 45 minutes, day and night.²⁰

The neighborhood sits on landfill, ground made by dumping earth and gravel into marsh and tidal flats. That is one reason flooding is a live question in Boston today (more in How cities are adapting to a changing climate).

Boston was also first with a new kind of network. On April 28, 1852, the city put into service an electric fire alarm telegraph, a system of street boxes wired to a central office so that pulling a box reported a fire's location at once.¹ William F. Channing invented it with help from Moses G. Farmer, and it started with 40 boxes.¹ The first alarm came in at 8:25 pm the next day.¹

Twenty years later, the network did not stop the city's worst fire. The Great Boston Fire began at 7:20 pm on November 9, 1872, at 83-87 Summer Street, and was contained around midday on November 10.²¹

It burned about 65 acres (26 hectares) and destroyed 776 buildings; reported deaths range from 26 to at least 30, and losses totaled $73.5 million at the time.²¹ The causes were a list of infrastructure failures: wooden mansard roofs, weak water pressure, too few hydrants with mismatched hose couplings, and alarm boxes that were kept locked.²¹ An outbreak of equine flu among the fire department's horses is often blamed, but a city commission found it caused only a few minutes' delay.²¹ Afterward, Boston widened streets, created Post Office Square and adopted limits on building height and area.²¹

In our reading, 1872 is the clearest early case in this guide of something that keeps coming back: the technology existed, and the way it was run held it back. A locked alarm box is a management decision, not an engineering one.

When did cities get gas, electricity and subways?

From the early 1800s to 1900, cities added a new layer of network roughly every decade, each with its own company, its own franchise and its own pipes, wires or tracks under the street.

• Gas light, London, 1807-1820s. In 1807, Frederick Winsor lit lamps on Pall Mall, using old musket barrels as gas pipes.²² The Gas Light and Coke Company, the world's first gas company, received a royal charter in 1812, and gas lit Westminster Bridge in 1813.²² By the 1820s, London had about 50,000 gas lamps on about 300 miles (480 km) of pipe.²²
• Underground railway, London, 1863. The Metropolitan Railway opened with 3.5 miles (5.6 km) of line between Paddington and Farringdon in January 1863.²³ Sources disagree slightly on the day: the National Lottery Heritage Fund gives January 9,²³ while many Underground histories treat January 9 as the ceremonial opening and give January 10 for the first public service.
• Telephone, 1876. Alexander Graham Bell's telephone patent was issued on March 7, 1876, and his notebook for March 10 records the words "Mr. Watson - Come here - I want to see you."²⁴
• Central power station, New York, 1882. Thomas Edison's Pearl Street Station began supplying customers on September 4, 1882.²⁵ On the first day it served about 85 customers and about 400 lamps; within a year it had 513 customers and about 10,000 lamps.²⁵ It ran on low-voltage direct current from six coal-fired dynamos and covered about a quarter of a square mile (0.65 square km) of lower Manhattan.²⁵ It was a central station: one plant serving many buildings over a network of wires, instead of each building making its own power.
• Electric streetcars, Richmond, 1888. Frank Sprague's Richmond Union Passenger Railway in Virginia began running in February 1888 and became the model for electric street railways.²⁶ By 1895 the US had almost 900 electric street railways on about 11,000 miles (17,700 km) of track, and horse-drawn street railways had nearly disappeared.²⁶

At the same time, two inventions let cities grow upward. The first passenger elevator was installed in 1857 in the Haughwout store in New York City, and elevators made buildings taller than four or five stories practical.²⁷

Then came the steel frame, a grid of metal columns and beams that carries a building's weight so the outer walls no longer have to. The Home Insurance Building in Chicago, designed by William Le Baron Jenney and completed in 1885, had 10 stories (later 12), and its frame combined wrought iron, cast iron and Bessemer steel beams; it was demolished in 1931.²⁸ PBS calls it the first tall building held up by a steel skeleton,²⁷ and it is often called the first skyscraper, though that title is debated, partly because its frame was mixed iron and steel.

The 1880s and 1890s pulled cities in two directions at once. Streetcars let people live farther out along the lines, in what became known as streetcar suburbs, while elevators and steel let downtowns stack higher. Both trends depended on the new networks, and both made the street overhead and the ground underneath more crowded.

In Boston: the first American subway and a reservoir

Richmond's streetcars had a direct effect on Boston: their success helped persuade the city to approve a large electrification project.²⁶ Electric cars soon clogged downtown, and Boston went underground. Construction of the Tremont Street Subway began on March 28, 1895, and it opened at 6 am on September 1, 1897, running from Park Street to Boylston, as the first subway in the United States.² More than 100,000 people rode it on the first day.² It was built to relieve streetcar congestion and modeled on lines in London, Glasgow and Budapest; the legislature appropriated $5 million, and the project came in early and under budget.²

Boston was also where the telephone first worked. On March 10, 1876, Alexander Graham Bell spoke the first intelligible words over an electric wire - "Mr. Watson, come here! I want to see you" - in the attic laboratory he shared with Thomas Watson at 5 Exeter Place in Boston.²⁹ An IEEE Milestone plaque now stands near Lafayette Place, at Avenue de Lafayette and Essex Street, and a separate marker at 109 Court Street marks the original laboratory where the two built their telephone equipment.²⁹

The networked era's biggest Boston project was water, and its cost fell on people far from the city. To build the Quabbin Reservoir in central Massachusetts, the state discontinued the towns of Dana, Enfield, Greenwich and Prescott on April 28, 1938.³⁰ About 2,500 residents left, and 7,613 graves were moved.³⁰ Flooding began in July 1939, and the reservoir was declared full on June 22, 1946.³⁰

It holds 412 billion gallons (about 1.56 trillion liters) on 80,443 acres (about 32,550 hectares) taken by eminent domain, the government's power to take private property for public use with payment, and it supplies 46 metro Boston communities.³⁰ Greater Boston's tap water still depends on a sacrifice made by people who never lived in the city (the system today is covered in Where your tap water comes from).

How did the car remake the city?

In the middle of the 20th century, governments in many countries rebuilt cities around the car. The US version was the largest. The Federal-Aid Highway Act of 1956 authorized "over 41,000 miles" (66,000 km) of interstate highways,³¹ and the federal government offered to pay 90% of the cost.³² With that much money on the table, states had strong reasons to build, and many urban routes were run through the neighborhoods that were cheapest to clear and had the least political power to resist.

In Atlanta, I-75, I-85 and I-20 destroyed downtown street grids and divided neighborhoods, and the areas cleared were mostly low-income Black communities.³¹ Overtown in Miami had an estimated 40,000 residents before I-95; about 8,000 remained after construction.³² Rondo in St. Paul, Minnesota, lost an estimated 600 family homes and 300 businesses to I-94.³² Syracuse's 15th Ward (I-81) and the neighborhoods along New York's Cross-Bronx Expressway are other often-cited cases.³² Across the whole program, the US Department of Transportation has estimated that more than 475,000 households, and over a million people, were displaced by federal highway construction.³² (That figure comes to us secondhand, through HISTORY.com; we could not locate the original DOT document.)

The same legal tools, eminent domain and federal money, were also used to clear areas labeled as slums under urban renewal programs. The two efforts often worked together, and in many cities it is hard to separate the damage done by one from the other.

The program's defenders and its critics are often describing the same roads, which sped travel between cities and suburbs for some people and demolished the homes of others.

Boston also had its own fight over new highways. The planned Inner Belt (I-695) was to be an eight-lane, mostly elevated loop of about 10 miles through Charlestown, Somerville, Cambridge, Brookline, the Fenway, Roxbury and the South End, and the eight-lane Southwest Expressway would have cost Roxbury 5,000 homes.³³

Residents, a coalition called the Greater Boston Committee on the Transportation Crisis, and groups including the Black Panther Party and the Black United Front in Roxbury organized against them.³³ On February 11, 1970, Governor Francis Sargent froze new construction and land-taking for a restudy, and on November 30, 1972, he cancelled both roads; Massachusetts then became the first state to put highway funds toward transit, including the Red Line extension to Alewife and the Orange Line relocation.³³

Boston's best-known highway story comes at the end of the century, when the city tried to undo part of the car era. The Central Artery/Tunnel Project, known as the Big Dig, replaced the elevated Central Artery (I-93) through downtown with tunnels.³⁴ It was conceived in the 1970s, begun in 1991 and completed in 2007, and Britannica calls it the largest and most expensive highway project in US history.³⁵ The Zakim Bridge was completed in 2003.³⁵ The cost depends on what you count:

In July 2006, a tunnel ceiling collapse killed a motorist and led to a $26 million settlement.³⁴ The project also freed about 300 acres (120 hectares) of land and turned the old highway corridor into the Rose Kennedy Greenway park.³⁴

Why did cities start cleaning up?

After about 1970, the main job in many wealthy countries shifted from building new networks to cleaning up and protecting the ones already there. In the US, the shift had a famous image. Ohio's Cuyahoga River burned at least nine times between 1868 and 1952.³⁶ A fire on June 22, 1969, helped build the movement behind the first Earth Day in 1970 and the founding of the US Environmental Protection Agency in December 1970.³⁶

The legal tool that followed was water law. The 1948 Federal Water Pollution Control Act was the first major US water pollution law, and its 1972 amendments, which became known as the Clean Water Act, required permits for point-source discharges, meaning pollution from a single identifiable outlet such as a pipe, and funded grants to build sewage treatment plants.³⁷ Congress passed it over President Nixon's veto.³⁶ In 1987, Congress replaced the construction grants with the Clean Water State Revolving Fund.³⁷ That move away from direct federal grants still shapes how US cities pay for water and sewer work, a subject covered in Who pays for the city.

In Boston, the law arrived through the courts. In the 1980s, combined sewer overflows, outlets where pipes carrying both sewage and rainwater spill into waterways when they fill up, sent about 3.3 billion gallons (12.5 billion liters) a year into Boston Harbor.³ The Massachusetts Water Resources Authority (MWRA) took over Greater Boston's water and sewer systems in 1985, and in 1986 federal Judge A. David Mazzone set a 13-year court-ordered construction schedule, which he oversaw until 2004.³

Dumping of sewage sludge into the harbor ended in 1991, and new primary treatment (letting solids settle out) began at Deer Island in 1995.³ Secondary treatment, which uses bacteria to break down dissolved pollution, started up in stages from 1997, and all of it was running in 2001-2005.³ Since 2000, treated effluent has traveled through a tunnel to an outfall 9.5 miles (15 km) out in Massachusetts Bay instead of into the harbor.³

The cleanup did not come from voluntary investment. It came from a lawsuit, a judge and a schedule. And as with the river fire, the harbor and the Great Stink, the action came after a visible failure.

What's changing now (2026): data and climate

The 2010s brought a new promise: the smart city, using sensors, data and software to run traffic, energy, water and other services. Some cities have folded these tools into everyday operations, and some projects ran into public resistance.

Much of this is now routine. Water and wastewater utilities run SCADA (supervisory control and data acquisition) systems that send sensor readings in real time and let a central control station monitor remote pump stations and the distribution network over a wide-area network.³⁸ In Boston, as of 2026, the 311 service center takes non-emergency requests by phone, online and through the BOS:311 app 24 hours a day, every day of the year, for problems from potholes and street lights to missed trash pickups.³⁹

The best-known case of resistance is Toronto. Sidewalk Labs, owned by Google's parent company Alphabet, proposed a waterfront district there called Quayside. Waterfront Toronto, the public agency in charge, limited the plan to 12 acres (5 hectares) from the roughly 190 acres (77 hectares) Sidewalk had proposed, and residents and advocates objected to its plans for collecting data.⁴⁰ Sidewalk Labs cancelled the project in May 2020, citing COVID-19 and economic uncertainty.⁴⁰ Supporters saw a chance to test new technology at scale; critics saw too much private control over public data.

Climate is now part of the job description of city government. London's Thames Barrier, a storm surge barrier of movable gates across the river, became operational in 1982, and as of November 17, 2025, it had closed 221 times for flood defense.⁴¹ Its operator's Thames Estuary 2100 plan sets out how flood risk will be managed to the end of the century and adjusts as sea-level projections change.⁴¹

In Boston, the city published Climate Ready Boston in December 2016.⁴² It projected rising relative sea levels even with sharp cuts in emissions, a growing risk of coastal flooding, and a possible tripling of heat-related deaths by 2050 without climate adaptation, meaning changes to infrastructure and planning that reduce the harm.⁴³ For a city that built Back Bay on filled marsh, the question of where the water goes is back where it started in 1814.

Each era added a layer to solve the problem of its day, and almost none of the older layers went away. A city in 2026 runs on all of them at once.

How this guide is organized

The rest of the guide takes those layers one at a time, starting with what comes into a building and ending with who pays for it. It begins with water, then power and light, then streets and signals, then transit, then waste, then emergencies and data. It closes with who runs it and pays for it: the agencies, authorities, workers and budgets behind every pipe and wire described here. Each chapter explains how its system works today, how it got that way, and what is changing now, with Boston as the running example.

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