On April 25, 1898 the United States declared war on Spain following the sinking of the Battleship Maine in Havana harbor on February 15, 1898. The war ended with the signing of the Treaty of Paris on December 10, 1898. As a result Spain lost its control over the remains of its overseas empire -- Cuba, Puerto Rico, the Philippines Islands, Guam, and other islands.
Beginning in 1492, Spain was the first European nation to sail westward across the Atlantic Ocean, explore, and colonize the Amerindian nations of the Western Hemisphere. At its greatest extent, the empire that resulted from this exploration extended from Virginia on the eastern coast of the United States south to Tierra del Fuego at the tip of South America excluding Brazil and westward to California and Alaska. Across the Pacific, it included the Philippines and other island groups. By 1825 much of this empire had fallen into other hands and in that year, Spain acknowledged the independence of its possessions in the present-day United States (then under Mexican control) and south to the tip of South America. The only remnants that remained in the empire in the Western Hemisphere were Cuba and Puerto Rico and across the Pacific in Philippines Islands, and the Carolina, Marshall, and Mariana Islands (including Guam) in Micronesia.