The tower in Arrés, which has been declared a Property of Cultural Interest (Bien de Interés Cultural) is all that remains of a Gothic castle-fortress dating from the second half of the 15th century. This 10-metre high tower, together with the tower in Atarés, defended the left bank of the Aragón river. It is made of ashlar and has arrowslits for firing with a bow and arrow or crossbow. The parish church of St Agatha is attached to the tower by the only section remaining of the defensive wall that surrounded the village. The dating of the structure does not correspond with the records of historical events which speak of an attack on the tower in Arrés in 1413 by Peter of Embún, loyal to Antón de Luna.

The tower was divided into three levels, although the floors and roof have since disappeared. Some mouldings and putlog holes have survived however. A very narrow doorway gives access to the building on the west side, under a rectangular window. On the first floor there must have been a magnificent chimney which sadly has not survived.

The rest of the village, conditioned by its defensive origins, has an unusual layout with gateways leading onto streets and a number (increasingly rare) of large, conical inglenook chimneys. The history of Arrés is determined by its position at the foot of the main Santiago Pilgrimage Route and at present, it has a hostal for pilgrims which is run by volunteers and friends of the “Camino”. From Arrés, the Pilgrimage Route continues to Mianos, Artieda and then the monumental village of Ruesta, the last stage of the Santiago Route in Aragón.