For the record, bubonic plague was a major cause of death until the mid-17th century.
We know a lot about London’s last visitation because the court official and diarist Samuel Pepys stayed in town and recorded what he saw around him. A century later, Daniel Defoe wrote a fictional account of what the plague had been like, A Journal of the Plague Year. London was never the same again, literally, since during the same time that the plague was ravaging and the wealthy were fleeing to their country homes to avoid it, fire destroyed much of the old medieval city. The oldest buildings in London generally date from the rebuilding effort begun after the fire.
The last remnants of folklore about the plague probably date from the final outbreaks. There’s the song “Ring around a rosy, pocket full of posies, ashes, ashes, we all fall down!” It seems to be talking about symptoms of bubos, the lymphatic swelling characteristic of the disease, and about the belief that smelling good air from flowers might ward off bad air of infection.
Bubonic Plague had a third major outbreak in the 19th century, when scientists could finally determine its cause: the Yersinia pestis bacterium, carried by members of the squirrel/groundhog family. The disease ravaged China and India, but did not create high mortality in Europe or the New World.
People can still die of it, but antibiotic treatment is now effective if it’s diagnosed in time. Get tested if you’re in close contact with or bitten by a squirrel, especially in the Western US.