I lived in Switzerland for four years, and in those four years I explored the country extensively. One of the places I visited frequently, because I lived relatively close by in Lausanne, was the Jura Mountains. Everyone knows the Swiss Alps, but the Jura is the other prominent mountain range in Switzerland, running along the France-Switzerland border from Basel to Nyon (roughly). And one of the most singular sights in the Swiss Jura is the Creux du Van:
I have read that it is the Grand Canyon of Switzerland (though that is normally reserved for the Rhine Gorge), but the Creux du Van is not a canyon at all; rather, it is a concave rock face or a cirque. If you look at it using Google Maps, its dramatic shape is quite evident. It sits in the canton of Neuchatel, in the Val-de-Travers (home of absinthe), and the pictures I took do not do it justice. The hike up and down are strenuous (about a 700-800 m change in elevation, at times quite steep), though not too difficult -- we started and finished in the village of Noiraigue, and ascended past la ferme Robert and through forests to the top. On the way down, we followed le sentier des quatorze contours, a series of switchbacks that quickly drops you back down to where you started. If you live in Switzerland or nearby France and have not done this hike, or if you are going to be in Switzerland and want to do something other than hit up the Hard Rock Cafe in Interlaken, I highly recommend it. The Val-de-Travers is a pretty neat place unto itself, where you can purchase absinthe, and visit a wonderful restaurant called La Truite that serves incredibly fresh truite au bleu, homemade absinthe ice cream, and local rosé wines.
For more info and some high quality topographical maps, check out the following links: