Yesterday NPR's Fresh Air interviewed Lee Jackson, author of Dirty Old London. Apparently my second-favorite city in the world came late to the sanitation party:
[B]y the 1890s, there were approximately 300,000 horses and 1,000 tons of dung a day in London. What the Victorians did, Lee says, was employ boys ages 12 to 14 to dodge between the traffic and try to scoop up the excrement as soon as it hit the streets.
This is the thing that's often forgotten: that London at the start of the 19th century, it was basically filled with these cesspools. There'd be brick chambers ... they'd be maybe 6 feet deep, about 4 [feet] wide and every house would have them. They'd be ideally in the back garden away from the house, but equally in central London and more crowded areas it was more common to have a cesspool in the basement. ... And above the cesspool would be where your household privy would be. And that was basically your sanitary facilities, for want of a better term.
He goes on from there.
Chicago, one should remember, also had disgusting streets, and nowhere to put sewers. Our solution? In the 1850s, we raised the city about 1.2 meters above the surrounding terrain. Note that it still took London 50 years to develop that level of sanitation.
Now London is one of the cleanest cities in the world. Still, people from outside the city—particularly from the north of England—refer to it as "the Big Stink." Cultural memories last for a long time.