Along with the rise of the famous 'robber barons' in the late 1800's was also the rise of the greatest period of American Imperialism which led to The Spanish American War. For months the media barons in the United States have railed against Spain's occupation of Cuba which was just 90 miles off the coast of Florida.
The American Battleship "The Maine" sank in Havana Harbor. The cause is unclear today. Back then it became a rallying cry for war against Spain who was accused of sinking the ship. Today there is some evidence that a broiler explosion on the ship caused its destruction. With that event, the demand for war against Spain swept the nation. The war lasted about ten weeks in Cuba and in the South Pacific.
At the end, Spain was badly defeated and America gained control over Cuba, Puerto Rico, The Philippines and Guam. Cuba quickly gained its independence but American was determined to hold on to its other processions.
The end of the Spanish American War immediately led to the Philippine-American War where at least 400,000 Filipinos (mostly civilians) died attempting to gain their independence from America. The Philippines would be an American territory until 1946.
Over 2,000 Americans died (mostly from disease) died in the Spanish American War and another 4,000+ died in the War against the Philippines.
The war had interesting other facts. Teddy Roosevelt rose to the Presidency because of his charge up San Juan Hill in Cuba! The American Navy became a world wide power. The war saw the extensive use of African American troops. Mark Twain wrote his famous anti-war short story "War Prayer" in opposition to the war (see video below).