After the Caribbean was visited by Christopher Columbus in 1493, Spain claimed the area, and its ships searched for treasure. With the Spanish discovery of the Pacific Ocean in 1513 the Caribbean became the main route of their expeditions and, later, of convoys. Pirates and warships of rival powers preyed on Spanish ships in the Caribbean. Although Spain controlled most of the sea, Britain, France, the Netherlands, and Denmark established colonies on the islands along the eastern fringe. The 1800s brought U.S. ships into the Caribbean, especially after 1848, when many gold-seekers crossed the sea to reach California via Panama.
After unsuccessful French attempts in the late 1800s to build a canal across Panama, the United States, in 1903, assumed control of the project. The 1914 opening of the Panama Canal paved the way for increased U.S. interest and involvement in this strategic sea, sometimes called the "American Mediterranean." Several Caribbean islands have U.S. military bases, many of which were established during World War II as support bases to protect the Panama Canal. The naval base at Guantanamo Bay, Cuba (est. 1899) is the oldest U.S. Caribbean base.
U.S. policy since the Monroe Doctrine of 1823 has been to exclude foreign powers from the Caribbean; however, in 1959, Cuba became the first country to come under strong foreign (Soviet) influence. U.S. intervention in the affairs of Caribbean countries, such as the Cuban Missile Crisis of 1962, the landing of U.S. marines at Santo Domingo in 1965 and at Grenada in 1983, and the U.S. invasion of Panama in 1989, reflects the region's importance in U.S. eyes.