Chengxi, China

This town in southern China is home to over 77,000 people packed into a relatively small 33 square kilometer area. The bureaucracy is a persistent headache, with the local government overseeing 6 residential communities and 9 villages. The subtropical climate may also be a turnoff for some, though the mild temperatures year-round could appeal to retirees. Overall, Chengxi offers an affordable cost of living but at the expense of personal space and red tape - it's best suited for those comfortable with dense urban living.