For centuries San Juan's Bay has served as one of Puerto Rico's main entry points for goods, people, and the exchange of ideas that comes from travel. Used as the main port during the Spanish colonial times, the bay is protected by the imposing Castillo San Felipe del Morro, a fort that to this day continues to welcome cruises and merchant boats to the Island of Enchantment. Some of the best views of the bay are found next to the romantic Paseo de la Princesa, a promenade that runs along the outside walls of Old San Juan.