Wieliczka and Bochnia Royal Salt Mines by Els Slots
Many caverns/galleries contain works of art, often altars and statues sculpted by miners/artists. We visited several levels by stairs or elevator, and saw many works of art, carved entirely out of salt.
Most spectacular was the Blessed Kinga Chapel, carved in one of the largest galleries. There were beautiful three dimensional 'salt' statues, such as the 'Last Supper'. The floor looked like a carefully laid tile design, but further examination shows it's salt carved to look like individual tiles. The huge chandeliers in this Cathedral are made of salt, each consisting of many dangling salt crystals.