The origin of the municipalities forming the Oarsoaldea Area: Errenteria, Lezo, Pasaia and Oiartzun dates back to the so-called Middle Ages.
The location of the region and its natural seafaring tradition has strongly influenced the outlay of the Old Parts of Pasai Donibane and Pasai San Pedro, each of which has one single street. Not forgetting its marine vocation, the Old Part of Lezo stands round its Holy Christ. In Errenteria, the street layout is influenced by the Parish Church of Nuestra Señora de la Asunción. In Oiartzun, the streets with their emblazoned houses stand round Church of San Esteban de Lartaun and the Pilgrims' Hospital.
These are the companies that offer guided tours to know these old towns: