Leukerbad Therme, Switzerland

Bathers crowd the outdoor pools of Leukerbad Therme, formerly the Burgerbad, beneath the green slopes of the Valais Alps. The village sits at about 1,400 meters (4,600 feet), and more than four million liters of warm water rise there every day. The complex has ten thermal pools between 28 and 43°C (82 and 109°F), plus water slides, which makes it the family-friendly choice among Alpine thermal baths.