Overlooking the sea, the San Carlos Bastion has stood tall in the city of Campeche since the 17th century. When the Spanish colonized the city, it became a major trading port in the Mayan region—and an easy target for pirates. The San Carlos Bastion is one of five built to protect the city. Unbearably hot, the bastion's sweltering basements became dungeons for buccaneers and criminals.

When the War of Independence arrived, the cities were left to their fate, and Mexican wealth declined along with piracy. The bastions were abandoned and the walls crumbled. It wasn't until the 20th century that the archaeological remains were recovered, and San Carlos became the City Museum.

According to superstition, aluxes (Mayan elf-like creatures) harassed the workers during the restoration process. The story goes that the workers built a series of Mayan temple-like structures in the basement to calm them. While the shrines are hidden from plain sight, visitors can spot them with the aid of a flashlight through a hole in the dungeon's basement.

In addition to artifacts from the city's history, the museum displays piracy exhibits and preserves the cannons used on the walls in battle.