From April to August 1898, the United States waged a war with Spain called the Spanish American War.
The United States went to war in part to help Cuba win its struggle for independence from Spain.
But the war was also prompted by American imperialists who wanted the United States to become a world power, with overseas colonies and global interests. The empire builders got their way.
As a result of the Spanish American War, the United States won control of Cuba, Puerto Rico, and Spain’s South Pacific colonies of Guam and the Philippines.
Cuba and the Philippines have since become independent countries, but Guam and Puerto Rico are still U.S. possessions.