Hong Kong’s Kowloon Walled City
The Hong Kong’s Kowloon Walled City had the highest human population density anywhere on the planet. An estimated of 50,000 people were said to live there within its walls. Kowloon was originally a military fort but British forces commandeered in 1898. When China announced intentions to claim it, refugees poured in by the thousands and the British couldn’t evict them so they pulled out.