Chapel of St. Kinga in Wieliczka Salt Mine, Poland
Before going down into the dark, many miners pray. (So would you.) It’s not uncommon for them to build chapels in the caverns they create, and the workers in this Polish salt mine took that task seriously, carving a 10,400-square-foot chapel into the crystalline walls. Józef Markowski started work on this particular chamber in 1896, handing it off to his brother Tomasz in 1920. Nearly everything in the room—from the chandeliers to the bas-reliefs—is carved out of rock salt. Wieliczka, which was a working mine from the 13th century until 1996, holds some 2,000 excavation chambers on nine underground levels, many decorated by miners with carvings and chapels dedicated to saints—and to those who lost their lives digging sodium chloride out of the earth.