Until the fifties, the “Irati” train passed through the
gorge through two tunnels carved into the mountains. Now the old train route
serves as a path through the gorge. You will find a 16C ruined bridge which,
according to legend, was built by the devil.
To visit Arbaiun, take the N178 Lumbier road and when
you reach Domeño, go towards Usún. Leading from the bridge of Usún there
is a very narrow path, 3km long, cut into the rock and which was the water
channel to Lumbier.
Arbaiun is a Nature Reserve, with 1,164
The river Salazar has cut a 6 kilometre long, 385 metre deep and 550 metre
wide canyon. It has a curious structure: the top part is exceedingly
vertical with sheer walls of hard limestone rock whilst the lower part is
softer, of a sandier limestone which is less resistant and permeable, making
it easier to wear away.
There is a great variety
of vegetation, predominantly oaks and holly oaks, beeches, kermes oaks, gall
oaks and boxwood.