Around the 14th century, erosion caused the mountain to collapse, leaving a reddish-hued rock basin in its place. Even today the ravine is still moving, and every year debris flows cause it to grow just a little larger. It is one of the most geologically unstable valleys in Switzerland. The Illgraben rock basin forms an abyss that is over 1,500 metres deep and is almost bare of vegetation.

Illgraben is a good hour's walk from Chandolin or Leuk /Susten. As soon as you reach the mountain peak you will be overwhelmed by the view. The Bhutanbrücke suspension bridge that spans the impressive ravine joins Upper Valais with Lower Valais at 134 metres. Generally the river that flows beneath seems rather unassuming, but in a matter of mere minutes it can become a torrential flood. This is one of nature’s wonders that requires a certain degree of caution.

Getting there: By public transport or car to Leuk, then walk.