Via Alta della Verzasca (Switzerland)
https://www.verzasca.net/articles/176_Via.Alta.della.Verzasca
Many people come from far away to take this 6-day (60km) hike, one of the wildest hikes you will find in Switzerland. Via Alta is a difficult hike, not for beginners. It goes along the ridge separating Val Verzasca from Valle Leventina, offering extraordinary views throughout the whole hike. You can sleep in the mountain huts along the way, the reservations are recommended in the high season.