Built under the reign of Felipe II, who commissioned the work to the Italian military engineer Fratín.Pentagonal in shape.Out of its five bastions, only three remain.There are two entrances, the main one orientated towards the historic quarter and the Socorro entrance.During the 18th century, it was converted into a prison for illustrious men such as the Count of Floridablanca, the Marquis of Leganés, etc. Today it houses a park and several exhibition rooms.
- Construction: Fortress
- Artistic period: Renaissance
- Historic period: 16th century
- From Monday to Friday From 07:30 to 21:30
- Saturday From 08:00 to 21:30
- Public holidays From 09:00 to 21:30
- Admission free