The Basque Country
When a group of diverse regions gets stitched together as one nation, it's often thanks to the grip of an iron fist. In the case of modern Spain, the man who held the line was the Generalissimo — the dictator Francisco Franco who ruled Spain from 1939 to 1975. One of the fascist's main challenges was to subdue the national aspirations of Spain's varied linguistic communities, particularly the Catalans and the Basques. In 1959, Franco's government banned the official use of the Basque language in a bid to further assimilate the people often referred to as Europe's first indigenous race. (The Basque language has no direct links to others spoken in Western Europe.)
Franco also outlawed the Basques' semiautonomous councils and their tax-collecting authority. As a result, an already vibrant independence movement started to gain steam and the terrorist group ETA was born. Operating out of Basque country in northeastern Spain — as well as a sliver of southwestern France — ETA placed bombs that indiscriminately killed roughly 820 people over a half-century of activity. But public revulsion over ETA's campaign sullied the image of Basque nationalism, and the group declared a cease-fire in September 2010, pledging to join the cause of furthering Basque autonomy through peaceful means in democratic Spain.