La Linea de la Concepcion, Spain

With a population of 64,499, La Línea de la Concepción is a blunt reality check for Americans seeking an easy life abroad. The city's close economic ties to Gibraltar mean residents contend with a persistent bureaucratic headache, as evidenced by failed attempts to impose a "congestion charge" on cross-border traffic. And while the climate is balmy, the air quality here has ranked among Spain's worst. This gritty border town is best suited for those willing to navigate its challenges.