A large, semi-sovereign, largely ungoverned urban enclave inside of Hon Kong, Kowloon Walled City was one of the most densely populated plots of land on the planet. Largely build in an ad-hoc, accretive manner over the years before it was finally torn down in 1994. Luckily for those of us who weren’t able to visit before it was destroyed, a group of Japanese researchers scoured the place, creating beautiful dense maps and diagrams of the city published in a book several years later, as well as enough detail to produce a 3D model of the city.

The images speak for themselves: