From Basel, Switzerland, to Mainz, Germany, a distance of some 242km (150 miles), the Vosges Mountains stretch along the west side of the Rhine Valley, bearing a similarity to the Black Forest of Germany. Many German and French families spend their summer vacation exploring the Vosges. Travelers with less time may want to settle for a quick look at the ancient mountains that once formed the boundary between France and Germany. They are filled with tall hardwood and fir trees, and a network of twisting roads with hairpin curves traverses them. The depths of the mountain forests are the closest France comes to wilderness.