Cubans have always been rebelling against Spain. A Cuban Patriot named Jose Marti started a war for Cuban's independence from Spain. Americans were biased towards the Cubans.
The main reason why Americans were so biased with the Cubans were because of the Yellow Press. Newspapers and Journals were created to exaggerate Spanish acts. These papers also had no info on the crimes the Cubans committed.
In 1898, a letter by a Spanish Ambassador was leaked and it was criticizing President McKinley. This letter was exaggerated as the worst insult in US history. The letter then started American Jingoism which was essentially a large hate towards Spain.
The Spanish-American War begins as people prepare to fight. Naval Officer George Dewey helped the US Navy Defeat the Spanish navy. They shot down the Spanish forces with ease killing at least 400 people.
As Dewey defeated the Spanish Navy, Emilio Aguinaldo led Filipino nationalists on their way to defeat the Spanish army. The Filipinos were fighting for freedom from Spain along with the Cubans.
As all of this is happening, President Roosevelt and his Rough Riders began to attack Spanish forces in Cuba. The Spanish troops attempted to flee. But, as they were surrounded and outnumbered by American troops, they were decimated.