Spanish explorer Hernando De Soto is said to have visited Hot Springs, Ark., in 1541, while searching for the Fountain of Youth. His quest wasn't successful, but mineral baths across the world have since been discovered by seekers of health and relaxation. Among the most famous spas, most of them still operative:

*Baden-Baden, West Germany: Set at the edge of the Black Forest, these springs are so hot they are used to help heat the town. The Romans first developed the springs, but the resort was most popular in the 19th century, when even prerevolutionary Russians -- who left their architectural mark on several of the city's villas and chapels -- came to take the cure and gamble at the casino.

*Spa, Belgium: Noteworthy for giving its name to all resorts with mineral springs, this town is also a jumping-off point for many nearby attractions: the ancient city of Lie ge, filled with church spires and bridges; Bastogne, site of the last desperate German offensive in World War II; and Verviers, where the Pageant of the Flying Cat -- marking the aviation experiment of a local chemist -- is celebrated every June.

*Fuji/Hakone/Izu National Park, Japan: Against the scenic backdrop of Mount Fuji, the numerous resorts in this area include such appropriately named hot springs as the Valley of Less Boiling and the Valley of Greater Boiling.

*Bath: England's only hot springs, this stately Georgian city -- set in an equally beautiful countryside -- offers the impressive Bath Abbey, good museums and the Royal Crescent, often called the single most beautiful street in England. As in Baden-Baden, the springs here were first appreciated by the Romans, whose extensive baths are an archeological highlight.

*Banff National Park, Alberta, Canada: When the government set aside 10 square miles in 1885 to protect the hot springs on Sulphur Mountain, it proved to be the beginning of Canada's national parks system. Now the Banff springs are surrounded by 2,500 square miles of spectacular scenery.

*Hot Springs National Park, Arkansas: A million gallons a day flow from the 47 springs in the park. The city of Hot Springs, surrounded by lakes and wooded hills, is a pleasant vacation spot in itself.