Wieliczka Salt Mine – Krakow, Poland
This World Heritage Site is remarkable and is certain to astonish visitors as there is no comparable place in the world quite like it. The Wieliczka Salt Mine has been mined continuously since the Middle Ages and miners have carved elaborate underground rooms and intricate sculptures within the Miocene salt. There is a gigantic subterannean cathedral carved entirely from salt including the floor, walls and decorations, with even the glowing chandeliers being made from salt crystals.
The Salt Mine in Wieliczka has always been extremely popular, from the 14th century when it was shown to the very privileged royal visitors, to today where a million visitors a year pour in to see the labyrinth of chambers, passages, and incredible structures made of salt.
All credit for this super cool info goes to:
http://www.oddee.com/item_97956.aspx
I thereby inform, I have just put this for sharing with everyone who finds this! Its not written by me.
Randomly Abstract 
Pakistan has salt mines toooo. Khewra is one of them. We went there and it was BEAUTIFUL! It was hot outside, but inside the temperature was cold, not normal, it was cold. Naturally cold! There was an entire restaurant who’s counters, shelves and everything was made out of salt. There was a MASJID made of salt!!!!!! There was a model of Minaar-e-Pakistan made of salt. And were small lakes too and salt bridges (real salt bridges, not the ones we use in an electrochemical cell 😉 ) over them.
http://www.google.com.pk/search?tbm=isch&hl=en&source=hp&biw=1280&bih=899&q=khewra&gbv=2&oq=khewra&aq=f&aqi=g10&aql=&gs_l=img.3..0l10.219.3639.0.3838.7.7.0.0.0.0.306.1157.1j1j3j1.6.0…0.0.Ogyju6shWio