The photos are from the route over the Bernina Pass to Poschiavo. Together with the Bernina Express via Alp Grüm and the Poschiavino Trail via La Rösa, the route is one of the most famous mountain bike routes in the Alps today. However, the basis for this was once laid by the muleteers with their trade routes 

Further information on the topic and the film can be found at renewildhaber.ch/stories/trail-history-hunters