These salt mines at the eastern edge of town were once owned by the Augustinian monastery. Operations began here in 1517. The deposits are more than 300m (1,000 ft.) thick and are still processed from four galleries or "hills." Visitors are given protective miner's clothing. Older children will enjoy the guided tours that begin with a ride into the mine on a small wagonlike train. After a nearly 1km (1/2-mile) journey, visitors leave the train and explore the rest of the mine, sliding down a miner's slide and riding on the underground salt lake in a ferry. The highlight of the tour is the "chapel," a grotto containing unusually shaped salt formations illuminated for an eerie effect. The 1 1/2-hour tour can be taken any time of the year, in any weather.