Piz Badus

Piz Badus or Six Madun is a mountain in the Lepontine Alps, lying on the border between the cantons of Uri and Graubünden.
In its northwestern face, which is the Graubünden side, lies Tomasee, source of the Anterior Rhine. 
It is possible to reach the lake on a path from Oberalp Pass, suitable for most walkers although still a mountain trail.