When I was recently in Edinburgh, we made a visit to Mary King Close, on the Royal Mile (high street). It is an very interesting, and curious place. To begin with, Edinburgh is built on a rock with the high (or main) street built along its highest point. Off the high street are a series of tiny streets, called "closes" that run perpendicular to the main thoroughfare.
They are more like alleyways than anything else, where mostly the poor made their residence in incredibly small cubicles. The closes were often named for prominent citizens, business people who acted as landlords. Mary King was such, offering tenement type living arrangements for townspeople, in 1630.
The Mary King Close residences were well beneath the city's street level, many stories down, as a matter of fact. The close was dark and dank, and a breeding ground for mystery and myths, and tales of ghosts. Many a person died down deep in the close, and there was disease and murder and bad dealings in abundance. At right and below is a model of the dwellings, above and below grade.
Though it was built in the 17th Century, it remained active until 1753, when it was eventually built over during a "modernization" period, and the lower floors became the foundation of the Royal Exchange (the City Chambers).
You can take the tour, venturing ever deeper into the dwellings. Life in 18th Century Edinburgh was difficult for many. The city was terribly overcrowded, and conditions in the close did not offer anything better. Until there were actual sewers, waste and trash were just thrown out the windows of the dwellings, down to the bottom floors. Only rain, when it rained, helped wash the stench and germs away. The Black Plague and bubonic plague ran rampant. It was obviously better to live on the upper floors, if a "residence" became available. As they say, it was fun to visit, but I wouldn't want to live there!
And, today, no one lives there, thank goodness, but for the ghosts!