Havana is a very old city. It was created in 1515 by Spanish explorers. Due to its important location it became a springboard for the Spanish conquest of the Americas. Also, it became a stopping point for Spanish ships returning to Spain filled with treasure. King Philip II of Spain granted Havana the title of City in 1592. Walls as well as forts were built to protect the old city. The sinking of the U.S. battleship Maine in Havana's harbor in 1898 was the immediate cause of the Spanish–American War.