This is one of the most spectacular gorges in the Navarre region (northern Spain), and it can easily be explored on foot along two clearly signposted routes.

The Foz de Lumbier is a short narrow gorge, 1,300 metres long, with vertical walls reaching a maximum height of 150 metres. Great birds of prey live in its crevices, cracks and ledges, including large numbers of griffin vultures. The gorge is also a haven for foxes, wild boar, badgers and Egyptian vultures. The flora includes an abundance of thyme and groves of poplars, willows and ash.

Unlike many other gorges, the Lumbier can be traversed by means of two simple footpaths at the foot of the cliffs. These are clearly signposted, although they lead through two tunnels without any artificial light.