The world-famous, 14th-century Heidelberg Schloss, an imposing castle nestled in a hill 300 feet above the city, draws visitors to this university town. On a clear day, from the castle's terrace or gardens, you can see not only the city, but also the Rhine River and the scenic Neckar Valley. Stroll through the old town, where you'll find narrow streets, market squares and plenty of shops, or hike in the adjacent forests and nearby hills.