The Navarrese Irurtzun locality has always been a point of confluence of ways between Navarrese grounds, of Alava and of Guipúzcoa, between the coast and the interior. Geographically, the Town has two elements that they characterize, the ravine of Two Sisters and the Erga, rocky summit that closes it for the north and dominates the entry of the whole vale of Arakil. Solitary and steep, on his rocks the chapel settles of Trinidad much venerated in the region and point of reference to montañeros of the area.
Irurtzun is the key of the beautiful vale of Arakil. Arakil, together with some other mountain vales, is one of the corners more typically Basque of the geography Navarre
Irurtzun in his most ancient part, still preserves large houses or hamlets that go back a XVIIIth and XIXth century.
It still preserves a bridge on the river Larraun, which consists of four semicircular arches of different styles. It is a little spoiled by the continuous reforms.
Another stone bridge along with the mouth. It is a type bridge medieval, of two stone masonry arches the lefthander and of half a point the right. It survives almost without modifications.
(Source Asier Alegui to see finished text in Web of personal interest).