Sant Ferran Castle
The construction of the castle began in 1753 under the orders of the highly distinguished military engineer Juan Martín Cermeño but it was not operational until 1792. It is one of the largest fortresses of its kind to be built in Europe. It has a symmetrical irregular pentagon layout with a double defence circuit composed of outer works of different types and sizes. The exterior perimeter measures 3,125 metres. In the moat the aforementioned outer works are found: two counterguards and seven ravelins, to which five counter mines and seven large-capacity water tanks are added.
The interior enclosure is made up of five large bastions and one smaller bastion (or platform), with a total perimeter of 2,100 metres. Seven large buildings for the accommodation of the garrison are arranged around the 12,000 m2 central parade ground. The garrison was composed of 4,000 men although the fortress could accommodate double that number if necessary. The 300-metre-long stables could accommodate up to 500 horses. The most spectacular feature of the monument for visitors is located underneath the parade ground: the extraordinary navigable water tanks, which could hold up to 9 million litres of water. Sant Ferran Castle was first opened to the general public in 1996 and has remained open on a regular basis since 1997. It is classified as a Cultural Asset of National Interest.