The area’s history dates back to the Roman era, when it was a Roman fortress; it was later the site of a Frankish count’s castle during the early Middle Ages. During the era when Spain was the principal European power, it was a Spanish bastion. During succeeding years, Luxembourg’s territory has at various times been part of France, Austro-Hungary, Germany, Belgium and the Netherlands. It was occupied by the Germans during both World Wars; during World War II it abandoned its policy of neutrality and joined the Allies, its government fighting the Germans from exile in London. Today it has an army of about 800 troops. Although small, Luxembourg has a diverse geography, including mountainous regions, a sandstone plateau, thick forests and rivers along and within its borders. A secular nation, Luxembourg’s population is largely Catholic, but there are also Protestant, Jewish, Greek and Russian Orthodox and Islamic people. The country’s economy features a high per-capita income, moderate growth, low inflation and low unemployment, and its per-capita gross domestic product is the highest in the world. Luxembourg boasts a number of museums and has produced several internationally known artists; perhaps the best-known was the late photographer Edward Steichen, whose famous Family of Man exhibition is now permanently housed in Clervaux.