Kowloon Walled City, 33,000+ Residents Lived Within 6.5 Acres

http://laughingsquid.com/kowloon-walled-city-33000-residents-lived-within-6-5-acres/

"Gutenberg, New Jersey is the densest United States town, with 56,000 people per square mile. Marine Division in Mumbai, India is currently the densest human inhabitance on earth, with ~300,000 people per square mile. Kowloon Walled City had a population density of 3.3 million people per square mile! Insane!"