Pay a visit to an ancient fortress that is now a cultural center, set amid grass and trees in a gorgeous green park.

Roam and relax amid the spacious surroundings of the Ciudadela, or citadel. This 16th-century fortress is in a vast urban park that encompasses, lawns, trees and moats. It is a popular spot for sports, leisure and cultural activities.

The extensive grounds cover approximately 69 acres (28 hectares), at the heart of which is the citadel. Surrounding this military stronghold is the glacis, an English-style park. Enjoy a walk or a jog along its paths or, if you want to do something a little more active, play some sports on the lawns.

Visit the citadel itself, which was constructed in the late 16th and early 17th centuries on the orders of King Philip II. The original structure formed a pentagon with five bastions in its corners, but two of these were demolished during an extension of the city. The building’s purpose was originally to defend Pamplona, but today some of its buildings host art and cultural exhibitions.

See what is on at the Polvorin, a former gunpowder storehouse, and the Sala de Armas, once a weapons building. The mixed pavilion, Pabellón de Mixtos, also occasionally hosts exhibitions. Investigate the fort's old bread oven which showcases avant-garde installations.

Continue your exploration of the fortress with a walk through its inner park. See the display of sculptures in the open-air exhibition space. Look for works by such prominent Spanish artists as Jorge Oteiza, Ricardo Ugarte and Pablo Juarros. Sit on a bench and take in the views, which include approximately 30 species of trees. For children, there is a small play area. View the citadel’s moats as you follow the central path, which also passes by ponds and sports facilities.

The Ciudadela is open every day except for a number of public holidays, and entry to the park and exhibitions is free. Get here from the city center quickly and easily on foot. Alternatively, take a taxi or drive and park for a fee in nearby lots.