El Morro, "The Bull," is officially named Castillo de San Felipe del Morro. This is the oldest fort in San Juan, with the first part built in 1539. It kept evolving until 1786. This guards the entrance to the wonderful harbor of the "rich port" (Puerto Rico.) Here the treasures of the Americas were loaded onto ships bound for Spain. In 1595 El Morro fought off a fleet led by Francis Drake.