ppearance 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
