Picture taken from > PizzaTravel (more pics there)
Salina Turda (Wikipedia page)
Salina Turda is a salt mine in the Durgău-Valea Sărată area of Turda, the second largest city in Cluj County, northwest Transylvania. Opened for tourists in 1992, the Salina Turda mine was visited by about 618,000 Romanian and foreign tourists in 2017.
Man if I were there I would be tempted to try lick the walls. To see if it’s salty.
That’s why we keep the walls super cold