Lies on the northwestern-most point of the islet of San Juan, Puerto Rico. Named in honor of King Philip II of Spain, the fortification, also referred to as el Morro or promontory, was designed to guard the entrance to the San Juan Bay, and defend the city of Old San Juan from seaborne enemies. In 1983, during the Reagan Administration, the castillo was declared a World Heritage Site by the United Nations in conjunction with the San Juan National Historic Site. Over two (2) million visitors a year explore the windswept ramparts and passageways making the castillo one of Puerto Rico's main visitor attractions. Facing the structure, on the opposite side of the bay, a smaller fortification known as El Ca?uelo complemented the castillo's defense of the entrance to the bay.
The construction of the Castillo San Felipe del Morro began in 1539 when King Charles V of Spain authorized its construction, including the surrounding walls. The purpose was to defend the port of San Juan.It was also constructed to control the entry to the harbor. Construction started the same year with a tiny proto-fortress that was "completed" in 1589. This small section comprises perhaps 10% of the structure people see today. In 1587, engineers Juan de Tejada and Juan Bautista Antonelli designed the actual appearance of the castle following well established Spanish military fortification design principles. Similar Spanish fortifications of the 17th-18th centuries can be seen in Cuba, Santo Domingo, Dominican Republic, Veracruz and Acapulco, Mexico, Portobello and Panama City, Panam?,and many other Latin American locations which were governed as part of the Spanish Empire during the Age of Exploration. The first fort of the Americas, Fort San Felipe, was built in Puerto Plata, Dominican Republic in 1540. Many complex additional new structures were added to El Morro over the next 400 years. The outer walls are six meters thick. In 1680, Governor Enrique Enr?quez de Sotomayor begun the construction of the walls surrounding the city of San Juan, which took 48 years. By the late 18th century, El Morro's walls had grown to be 18 feet (5.5?m) thick. Today El Morro has six levels that rise from sea level to 145 feet (44?m) high. All along the walls are seen the dome-covered sentry boxes known as garitas, which have become a cultural symbol of Puerto Rico itself. The El Morro or Port San Juan Light was built atop the castillo in 1843, but in 1908, it was replaced by the US military with the current lighthouse. The original lighthouse was destroyed by US warship fire during the 1898 bombardment of the city. Including the exterior open killing grounds, known as the glacis and esplanade, dominated by cannon in the 17th and 18th centuries, El Morro can be said to take up over 70 acres (280,000?m?).
During the Spanish occupation of the island, El Morro survived several attacks from foreign powers on various occasions. In 1595, englishman Sir Francis Drake attacked San Juan with his fleet. He failed, however, the Spanish gunners shot a cannonball through his cabin. In 1598, the English attacked again, led by George Clifford, 3rd Earl of Cumberland. Clifford succeeded because he entered San Juan through land instead of entering through the San Juan Bay and El Morro. However, an epidemic of dysentery forced him to flee the island.
The Dutch, led by Boudewijn Hendricksz, also attacked the island following George Clifford's idea of invading through land. To the amazement of the citizens, the invaders were able to pass in front of the castle's defenders and into the harbor, where the city's cannon fire could not reach them. El Morro managed to resist the siege and eventually make the Dutch retire, although the they were able to sack and burn the city before leaving.
El Morro's last active fight occurred during a naval bombardment by the United States Navy during the 1898 Spanish-American War. Ending the age of naval warfare in the Caribbean, at least in the classical sense. During the Spanish-American War, the castle was attacked at least three times by American naval forces, the most major of which being the Bombardment of San Juan on May 12, 1898.
El Morro and many other Spanish government buildings in Old San Juan then became part of a large U.S. Army post, called Fort Brooke. In the early 20th century, the U.S. military filled up the esplanade, or green space in front of "El Morro" with baseball diamonds, hospitals, officers' quarters, an officers' club and even a golf course.
United States' first shots of World War I were fired from the castillo's battery in 1915. On March 21, 1915, Lt. Teofilo Marxuach was the officer of the day at El Morro Castle. The Odenwald, built in 1903 (not to be confused with the German World War II war ship which carried the same name), was an armed German supply ship which tried to force its way out of the bay and deliver supplies to the German submarines waiting in the Atlantic Ocean. Lt. Marxuach gave the order to open fire on the ship. The Odenwald was forced to return and its supplies were confiscated. The shots ordered by Lt. Marxuach have been considered as the first fired by the United States in World War I. The first actual wartime shot fired by the U.S. came on the day war was declared, during the Scuttling of SMS Cormoran off another small American island, Guam.
During World War II the United States Army added a massive concrete bunker to the top of El Morro to serve as a Harbor Defense Fire Control Station to direct a network of coastal artillery sites, and to keep watch for German submarines which were ravaging shipping in the Caribbean. A lighthouse, rebuilt by the U.S. Army in 1906?08 is the tallest point on El Morro, standing 180 feet (55 m) above sea level. Flagpoles on El Morro today customarily fly the United States flag, the Puerto Rican flag and the Cross of Burgundy Flag, also known in Spanish as las Aspas de Borgo?a, a standard which was widely used by Spanish armies around the world from 1506?1785.
In 1961, the United States Army officially retired from El Morro. The "fort" became a part of the National Park Service to be preserved as museums. In 1983, the Castillo and the city walls were declared a World Heritage Site by the United Nations. In honor of the Quincentennial of the voyages of Columbus in 1992 the exterior esplanade was cleared of palm trees that had been planted by the U.S. Army in the Fort Brooke era, and restored to the open appearance this "field-of-fire" for El Morro's cannon would have had in colonial Spanish times. Parking lots and paved roads were also removed, and the El Morro lighthouse repaired and restored to its original appearance. El Morro was used as a film set in the 1996 motion picture Amistad. Steven Spielberg used it to represent a fort in Sierra Leone where African slaves were auctioned in 1839. African slave labor was used in addition to local labor to help build the castillo. El Morro was a defensive military fortification and a major component of San Juan's harbor defense system. Puerto Rico as such was considered by the Spanish crown as the "Key to the Antilles"; no enemy ship could navigate its waters without fear of capture.