Declared a National Monument. Since 1948 it has housed the Fisherman's Museum. The Tower of Ercilla is an example of the Basque medieval civil architecture.Belonging to the family of the famous poet D. Alonso de Ercilla. Built in Gothic style. After diverse restorations, it now houses the Fisherman's Museum exclusively dedicating its exhibits to show the visitors the environment, life and work of the arrantzaleak or Basque fishermen.
The ground floor houses the rooms related with the environment and life of the fisherman on land.The other floors exhibit aspects such as the fishermen trade unions, the fishing activities and techniques up to the present day, the vessels, navigational instruments, etc. There is a room dedicated to the Tower and to the illustrious individuals who resided in it.