Wieliczka is a salt mine a few kilometres from Kraków, in southern Poland, worked for seven centuries by miners who cut chapels, statues and chandeliers out of the same rock salt they were digging, and its tunnels run for 300 kilometres under the town, with a full church a hundred metres down. The mine opened in the thirteenth century and was one of the great enterprises of the Polish crown, salt being money; it closed as a working mine in 1996 and is now walked on a route of about three kilometres through some twenty chambers, reached by a wooden staircase of 380 steps and left by a miners' lift. The chambers are the miners' own work. Over the centuries they carved altars and saints from the salt to pray at before shifts, and the tradition grew until St Kinga's Chapel, cut between 1896 and 1963 by three miners, became a full underground church 54 metres long and 12 metres high, with a salt floor, salt reliefs of the Last Supper, and chandeliers of salt crystal hanging from the roof; Mass is still said there, couples marry in it, and the salt walls give concerts a remarkable acoustic.
The legend behind the name is Kinga, a Hungarian princess who threw her engagement ring into a salt mine at home before marrying into Poland and, the story goes, had the ring found again in the first lump of salt dug at Wieliczka. Away from the carved halls the route passes natural grottoes where pale clusters of salt crystal bristle from the ceilings like frost, underground lakes of brine, and a vertical shaft braced entirely in stacked timber, log crossed over log with no metal, the way the miners held the rock up for centuries. Old ore-cart tracks run down timber-lined corridors, and the air is cool and salted; ventilation added in the nineteenth century once let in damp that began dissolving the carvings, and the mine now controls its own weather. Wieliczka is a mine that its miners turned into a cathedral, and the walls are still edible.