America had an interest in Cuba. The Americans offered to buy Cuba, but Cuba responded that they would rather see their precious and sink in the ocean. American was still interested, and so when the Cubans rebelled against Spain they went to the Cubans to help. The revolt was not successful, but after the Cuba was resolved America started to invest millions of dollars in sugar cane plantations.
The U.S.S Maine was ordered to get American's that might be in trouble from the war from Cuba, In February the ship blew up and killed everyone on it,
Journalists began embellishing stories to get sympathy from America. They lied and made things up. This has become known as Yellow Journalism.
The rough riders were a volunteer cavalry under the control of Theodore Roosevelt