What major event led the U. S. to join the Spanish-American War? Who did the U. S. support during the war? What did the U. S. gain after winning the war?

On April 21, 1898, the United States declared war against Spain. ... The reasons for war were many, but there were two immediate ones: America's support the ongoing struggle by Cubans and Filipinos against Spanish rule, and the mysterious explosion of the battleship U.S.S. Maine in Havana Harbor.

Hostilities began in the aftermath of the internal explosion of USS Maine in Havana Harbor in Cuba, leading to U.S. intervention in the Cuban War of Independence. The war led to the U.S. emerging as predominant in the Caribbean region, and resulted in U.S. acquisition of Spain's Pacific possessions.Includes event: Battle of Santiago de CubaCombatants: Spain, United States

it was known as the aztec empire. the capital was formally named tenochtitlan. *hope this .