Oil production was not the only economic value of Alaska's land, however. In the second half of the 20th century, Alaska discovered tourism as an important source of revenue. Tourism became popular after World War II, when military personnel stationed in the region returned home praising its natural splendor. The Alcan Highway, built during the war, and the Alaska Marine Highway System, completed in 1963, made the state more accessible than before. Tourism became increasingly important in Alaska, and today over 1.4 million people visit the state each year.