San Carlos Fortress

San Carlos Fortress is a stone fortification featuring thick defensive walls, watchtowers, and a central courtyard with military structures and storage buildings arranged around it. Its distinctive star-shaped design follows European military architecture meant to protect against cannon fire from multiple angles.

Spanish colonial authorities ordered construction in the early 1770s, with the fortress completed in 1776 to secure coastal trade routes. This period marked Spain's effort to strengthen military control across its Mexican territories.

The fortress displays military history through exhibits spanning from colonial times to modern conflicts, showing how this structure served Mexico's defense needs across centuries. Visitors encounter objects that document different periods of strategic importance.

The site is open most weekdays and offers guided tours explaining the architecture and military function. Comfortable shoes are recommended since walkways include stairs and uneven stone surfaces.

During World War II, the fortress served as a detention camp for German and Italian nationals after Mexico joined the Allied forces. This lesser-known role demonstrates how the structure adapted to different purposes across the centuries.