Castle of San Luis de Bocachica, Colonial fortress at Bocachica Bay, Cartagena de Indias, Colombia

The Castle of San Luis de Bocachica was a Spanish military fortress on Tierra Bomba Island, begun in 1646 by engineer Juan de Somovilla to guard the Bocachica channel into Cartagena harbour. Its low stone walls, broad crenellations and arched entrance survive as ruins; the site also holds the later Castle of San Fernando, built from 1753.

Construction of the castle began in 1646 under engineer Juan de Somovilla and was named after governor Luis Fernández de Córdoba. French forces and pirates took it in 1697 after a two-day siege, and in 1741 British artillery and ships destroyed it. From 1753 engineer Antonio de Arévalo built the Castle of San Fernando de Bocachica over its ruins, completed in 1759.

The fortress displays Spanish military architecture from colonial times with stone walls still visible today. The construction shows how Spain maintained control over trade routes and protected the city from outside threats.

To visit the fortress, take a boat from Cartagena to Bocachica where you can explore the site. The location sits on an island, so a boat is the only way to reach it.

The fortress was the main control point for all deep-water ships entering Cartagena Bay. This strategic location made it one of Spain's most important defense positions in South America.