For a dose of nature blended with history, check out the St. Beatus caves. Their legend goes back to the 6th century, when the missionary St. Beatus arrived on the Thunersee to find the local population terrorized by a dragon that lived in the lake and surrounding grottoes. Exorcised by Beatus, the fleeing dragon fell to his death on the rocks. Today you can see the stalagmites, stalactites, and pools inside, as well as a colorful rendering of Ponzo, the dragon. The on-site cave museum offers scientific and historical information about caves around the world. Take a jacket, as it's cold inside the caves. You can reach them by taking Bus 21 from either train station or by crossing by boat from the Interlaken West station to Sundlaunen, then a 20-minute hike to the caves.