Caldas Novas, Brazil

With a population of just 24,159, Caldas Novas bills itself as the world's largest hydrothermal resort, drawing up to 300,000 visitors during Carnival. But behind the glitzy marketing lies a persistent bureaucratic headache - the city government includes a mayor, vice-mayor, and 10 councilmembers overseeing a complex web of "villages" and "hamlets." And while the hot springs may be a major draw, the region's geology also means the local water table is under constant scrutiny, with concerns that nearby dams could cool the thermal springs. For those seeking an authentic Brazilian experience beyond the tourist traps, Caldas Novas may not be the ideal destination.