Sanya, China

With a population of over 1 million, Sanya is a bustling resort city in southern China, but the tropical climate and tourism-driven economy come with trade-offs. Bureaucracy is a persistent headache, with officials cracking down on tourist scams at local restaurants. The city's coastal location also makes it vulnerable to rising sea levels. Still, Sanya's beautiful beaches, luxury resorts, and Buddhist landmarks attract visitors seeking an exotic escape - but its charms may not outweigh the hassles for those looking to put down roots.