Annecy sits on the northern edge of the third largest lake in France, surrounded by the Alps on all sides and crisscrossed by the channels of the Thiou river that flow through the historic core. The water in the lake is so clean that it was once used as a drinking water source, and you can still feel that when you jump off the pier in August. The old town is compact and flat — no staircases, no major inclines — making it one of the rare historic centers you can wander without planning a route. The city also serves as a base for cycling, paragliding, and boat tours, so it is no wonder that tourists flood it in summer; if you can, come in May or September.