The salt mines at Wieliczka have been worked for more than 700 years, and comprise more than 2,000 chambers distributed through nine working floors. Parts of the mine have been opened to the public since the late 19th century. Visitors now followed a route 4 km long, passing through the St Antonia Chapel of 1689 and the Blessed Kings’ Chapel, both decorated with bas-reliefs of biblical subjects carved from the salt. In some chambers there are displays of old equipment, including huge 18th century horse gins, and a brake wheel from a 19th century inclined plane. There are also displays of minerals and hand tools, and a copious archive.