Ever heard of Kowloon Walled City? It was a Song Dynasty outpost, which became one of the most densely populated places in the world by the 1980s (50,000 residents occupying 7 acres). Here are a couple pics:
Note the incredible density of the structures - it appears that hundreds of structures were built on top of each other in patchwork fashion.
The wall, which originally surrounded the city, was recycled by the Japanese during their occupation of China during WWII. After the Japanese withdrew from China, thousands of squatters descended on the city, and its population burgeoned.
These images illustrate the way business was done in the city. Clearly, business was not regulated. Imagine growing up in a place like that - what an eerie thought.
Kowloon Walled City was rife with gambling, drug use, and prostitution. It was controlled by Triads. Otherwise, it was largely ungoverned.
Note the rag-tag manner in which the utilities (electrical and water lines) are strung up. Boggles the mind.
Unfortunately, this gem of urban planning was torn down in 1993-94 by governing authority in Hong Kong. The reasons cited were the walled city's high crime rates and terribly unsanitary conditions. Residents were given, in aggregate, about $330 million in compensation, which translates to roughly $11,000 per person - the population of the walled city had declined to about 30,000 by the early 90s.