Spain's powerful world empire of the 16th and 17th centuries ultimately yielded command of the seas to England. Subsequent failure to embrace the mercantile and industrial revolutions caused the country to fall behind Britain, France, and Germany in economic and political power. Spain remained neutral in World Wars I and II, but suffered through a devastating civil war (1936-39). In the second half of the 20th century, Spain has played a catch-up role in the western international community; it joined the EU in 1986. Continuing challenges include Basque Fatherland and Liberty (ETA) terrorism and further reductions in unemployment.