Huaihua, China

With a population of over 4.5 million, Huaihua is a sprawling metropolis in western Hunan that will test the resolve of any foreign resident. The city's remote location and mountainous terrain make it a transportation hub, but the climate is oppressive, with long, hot and wet summers. Bureaucratic headaches are a persistent challenge, as Huaihua is home to a major military base and nuclear assets. While the city boasts natural beauty in its surrounding forests, this provincial capital is not for the faint of heart - only the most adventurous expats need apply.