Lake Constance, Germany

With 125 miles of shoreline that touches Switzerland, Austria, and Germany, Lake Constance is one of the few places in the world where you can have breakfast, lunch, and dinner in three different countries. The hilly landscape is dotted with castles, monasteries, and picture-perfect medieval villages like Meersburg, where ancient city walls give way to terraced gardens that tumble into the lake. It’s easily reached by ferry from Konstanz, the largest city on the lake and home to sophisticated restaurants and hotels. Don’t miss Mainau Island, a 96-acre Eden known as the Flower Island.