Walled City

http://www.spoon-tamago.com/2014/10/28/detailed-cross-section-of-the-kowloon-walled-city-created-by-japanese-researchers/

http://www.mascontext.com/issues/19-trace-fall-13/kowloon-walled-city-heterotopia-in-a-space-of-disappearance/

http://www.dailymail.co.uk/news/article-2139914/A-rare-insight-Kowloon-Walled-City.html

https://news.ycombinator.com/item?id=8580136