Remington, Charge Up San Juan Hill

The special interest in Latin America that the Monroe Doctrine proclaimed brought major changes to the United States in 1898. The United States declared war against Spain in what was called the Spanish American war - John Hay called it that "splendid little war". When Spain surrendered its remaining possessions in the Western hemisphere to the United States, the young nation joined the European powers as an imperialist nation. It acquired Cuba, Puerto Rico, the Philippine Islands, and the Carolina, Marshall, and Mariana Islands (including Guam) in Micronesia.

It began with Cuba. 

Part of Uncle Sam Plants the Flag: Imperialism in Latin America