What event fueled American jingoism and inflamed relations with Spain?

On February 15, 1898, the American battleship USS Maine, which was stationed in Havana harbor, exploded and sank, taking the lives of 266 crew members. Although the cause of the explosion was never definitively determined, the United States quickly attributed it to an external attack by the Spanish and used the incident as a pretext to declare war on Spain on April 25, 1898.