In the past, you often took your life in your hands going through the Twingi in winter. Until the tunnel was built between Ausserbinn and Binn (1965), the remote valley was often cut off from the outside world for weeks at a time in winter.
A forest trail leads from Betlis village to a vantage point, opening up a vista to a gigantic water spectacle. The Seerenbach thunders over the vertical cliff face on the northern shore of Lake Walen, cascading 585 m in a series of stages down to Betlis to join the waters of the Rin Spring.
The Gastern Valley (Gasterntal) can only be accessed via the narrow Chluse Gorge on foot or by bus from the Kandersteg Railroad Station.