Castillo de Irulegui stands atop Monte Irulegui at 893 meters altitude in the Valley of Aranguren, Navarra, commanding strategic views across the Pamplona Basin. Built on the remains of an ancient Vasconian Iron Age fort, the castle features a distinctive pentagonal keep that was remodeled in the 14th century into a rectangular structure with five circular corner turrets. Serving as a vital medieval surveillance watchtower for transmitting signals across Navarre, the castle was destroyed at the end of the 15th century during internal nobility conflicts and remains one of the clearest examples of Kingdom of Navarra medieval fortifications.
