The City Museum is located in Baluarte de San Carlos, the first one built in 1686 with a clear Baroque style.

The bulwark was dedicated to King Carlos II of Spain. 

It is currently the only bulwark accessible through a modified ramp that goes from the street to the first level of the building.

The architectural plan of this property is pentagonal. The bastion has a parade ground, a ramp, a space for the guardhouse, a walkway and a gorge, the latter demolished in the middle of the last century and rebuilt in the year 2000. 

It features huge wooden doors, three rooms, a "purguero" (a drainage system), an access embankment, as well as two large watchtowers, and is surrounded by battlements. 

The museum exhibition is related to the history of the city, with a focus on episodes related to pirates.

In this museum, you will find various items from the colonial era such as armor and cannons from those centuries.

A prison known as "el pulguero" (the flea pit), where prisoners were held, worth a visit. Currently, there are some representations that allow you to transport yourself to that time.