Salt has been mined here for around 1,000 years, and the oldest shafts date from the 13th century. In the Middle Ages, salt was a highly sought-after commodity, and much of the splendor of Kraków was financed by the white powder mined here. Commercial mining has since been abandoned, and the only salt extracted here now is sold to visitors. The tour takes about 2 hours and begins with a long descent into the mine on foot. The tour takes you down about 130m (427 ft.), but the mine itself is much deeper, going to a depth of some 300m (984 ft.). The highlights of the tour include hundreds of statues sculpted by the miners over the years, as well as underground lakes and incredibly ornate chambers and chapels, the most impressive of these being the Chapel of St. Kinga. Visits are by guided tour only. Polish-language tours run throughout the day; English-language tours are less frequent but still often enough (at least, in summer) that you won't have to wait very long (the last English tour is at 6pm). In winter, English-language tours are provided hourly from 9am to 5pm. Be sure to pack a sweater since it's cool down there, and wear comfortable shoes for climbing stairs. Claustrophobics should obviously think twice, but mild cases shouldn't have any problem, since the chapels and tunnels are large and well ventilated.