Poland: Bochnia Salt Mines

The Bochnia Salt Mine  in Bochnia, Poland, is one of the oldest salt mines in the world and is the oldest commercial company in Poland. The Bochnia salt mine was established in 1248 after salt had been discovered there in the 12th and 13th centuries, and became part of the royal mining company, żupy krakowskie (Kraków Salt Works). In 1990 the mine ceased producing salt but remains a tourist attraction.In 1981 the Bochnia salt mine was declared a heritage monument. It is one of Poland's official national Historic Monuments (Pomnik historii), as designated on 6 October 2000, and is overseen by the National Heritage Board of Poland. The chapel in the mine has train tracks running through it.

Thanks to Mr Sebastine. He has 2 stamps. One on the right is from 2021 and was issued during Tokyo
 Olympics. And one on the left is on Winter Olympics issued this year.