In 1858, London experienced an unprecedented environmental crisis known as “The Great Stink.” An unbearable heatwave caused the River Thames to reek so intensely that it left residents gasping for air, ultimately forcing the city to develop a modern sewer system that would revolutionize public health.
The stench was so overwhelming that those who could afford it fled the city. Those who remained resorted to soaking curtains in lime chloride and pressing handkerchiefs over their noses when venturing outdoors. The local press vividly described the horror, stating, “Whoso once inhales the stink can never forget it, and may count himself lucky if he live to remember it.”
For weeks in 1858, temperatures soared above 30 degrees Celsius (86 degrees Fahrenheit) with no rain to alleviate the heat or wash away the accumulating filth. London’s vital River Thames transformed into an open sewer, a murky concoction of human and animal waste, garbage, and industrial pollution. The relentless heat drove the river to unusually low levels, exposing decaying sewage and refuse along its banks, which fermented in the summer sun, blanketing the city in a suffocating haze.
The root of the problem lay in London’s rapid growth and outdated infrastructure. Between 1800 and 1850, the city’s population doubled to 2.5 million, making it the largest city in the world. However, its hopelessly overwhelmed sewer system could not cope, with waste from homes and businesses flowing directly into the Thames. The increasing popularity of indoor flush toilets among wealthier households only exacerbated the issue, as human waste was flushed straight into the river, a stark contrast to earlier centuries when “night soil men” emptied cesspits.
At high tide, polluted water frequently washed back onto the streets. While Londoners were accustomed to a foul-smelling Thames, the Great Stink surpassed anything they had ever known. Charles Dickens, in his novel Little Dorrit, captured the grim reality, writing, “Through the heart of the town a deadly sewer ebbed and flowed, in the place of a fine fresh river.” Despite the appalling conditions, people continued to wash in and even drink from the river.
During the summer of the Great Stink, outbreaks of dysentery, typhoid, and the dreaded cholera spread rapidly. At the time, the prevailing belief, dating back to ancient Greece, was that diseases were caused by breathing foul-smelling air, or “miasmas.” However, physician John Snow had observed a different pattern during earlier cholera epidemics between 1831 and 1854, which claimed over 30,000 lives. In London’s poor Soho district, Snow noted that about 500 people died after overflowing cesspits contaminated a neighborhood water supply.
Snow became convinced that cholera spread through polluted drinking water, not bad air. He famously had the handle removed from the Broad Street water pump, effectively ending the local outbreak. He later mapped cholera deaths near other public pumps, finding the same pattern. Despite his groundbreaking work, few politicians accepted his theory, and Snow himself died in June 1858, just before the Great Stink reached its peak.
For years, London’s Metropolitan Board of Works had urged lawmakers to modernize the city’s sewer system, but Parliament repeatedly refused to fund the project, prioritizing grand monuments over underground infrastructure. This changed dramatically when lawmakers themselves experienced the terrible stench. The recently completed Palace of Westminster, home to Parliament, stood directly next to the Thames. The smell became so overwhelming that lawmakers abandoned the building and fled to the countryside.
Finally, they approved the decision they had delayed for years, resolving to free London of the river’s “noxious exhalations.” Within just 18 days, Parliament passed legislation allocating £3 million to construct a new sewer system. Engineer Joseph Bazalgette was chosen to lead the monumental task.
Bazalgette designed nearly 1,800 kilometers (1,100 miles) of underground sewers, intercepting waste from streets and buildings before it could flow into the Thames. He also constructed embankments and riverside promenades that concealed the main sewer lines while protecting the city from flooding. Additionally, he built two enormous pumping stations to lift wastewater through the system. The Abbey Mills Pumping Station, completed in 1868, became known as the “Cathedral of Sewage” for its striking architecture, symbolizing a triumph over filth, disease, and polluted streets.
By 1875, the project was complete. Bazalgette had built what was then the world’s most advanced sewer system, remarkably planning for London’s future by designing it to serve a population 50% larger than the city had at the time—approximately 4.5 million people. From that point on, cholera became a relic of the past.
More than 150 years later, nearly 9 million people now live in London, and Bazalgette’s Victorian pipes have struggled with the demands of modern life, often clogged by everything from sanitary pads and diapers to condoms and food waste. Despite later expansions, his system remained the backbone of London’s wastewater network until 2025, when the 25-kilometer Thames Tideway Tunnel opened to relieve pressure on the historic sewers, ensuring that no one in London will ever have to experience the Great Stink again.
This article was originally written in German.
