The idea of spending a couple of hours 135 meters (430+ feet) under the earth in a salt mine was not especially appealing to me. However, everything I read and heard about a visit to the Krakow region of Poland told me to go. So I did. And in so doing, I understand I extended my life by a couple of minutes or so. Unlike coal mines, there are apparently health benefits to the salt air, and they operate a health spa in the mine where people with respiratory problems can come for treatment. I did find the air refreshing and easy to breathe. However, too much salt, and I guess you could end up too well preserved like this fellow! Just kidding.
Salt has been a highly prized substance throughout history, as it not only preserves, but adds flavor. Even Christ spoke of salt losing its savor. So to find a huge deposit of salt in one's land pretty well guaranteed prosperity. Mining at Wieliczka started in the Middle Ages. By 1640, a main haft was sunk to 135 meters (the current tourist route), although the mine now goes to 327 meters. Nicholas Copernicus, the great Polish astronomer, visited in 1493 when he was a university student. Since that time, the mines have continued to attract the great and the humble to see its wonders. 
Some chambers demonstrate through salt carvings how the salt mines operated in early times. Others contain magnificent carvings to depict historical events or important people. And someone with good sense of humor placed a few salt gnomes around to keep an eye on things. A number of carvings represent religious themes. While it is an easy and safe walk through the chambers today, there were many dangers to the early miners, particularly methane gas which had to be burned out before the miners could advance.
Using a chamber dug out in the 17th century, Mieczyslaw Kluzek carved in 1967 six life size salt figures, telling the legend of the finding of the salt. Kinga, the daughter of Bela IV, King of Hungary, was betrothed to the Duke of Cracow in the 13th century. Kinga received a salt mine in as part of her dowry into which she threw her engagement ring (I wonder what the Duke thought of that). According to the story, the ring and salt deposits miraculously traveled to Wieliczka. When she came Cracow, she ordered the miners to dig in a particular spot in Wieliczka, and they found her ring as well as the salt mine. St. Kinga became the patroness of miners and was canonized in 1999 by Pope John Paul II. 
The most spectacular chamber, though, is St. Kinga's Chapel, near the end of the tourist trail. The huge chamber was carved out in 1896 and for almost 70 years, miner sculptors created a chapel entirely from salt. It contains remarkable statues and bas relief of scenes from Christ's life and is lit with elegant chandeliers made with salt crystals which causes the salt floors to shimmer. In the past decade, additional sculptural projects have been completed. It is difficult to describe the beauty of this glimmering chapel. Photos do not do justice, as the shimmer of the salt causes reflections that hide the depth and remarkable detail of the carvings.
Leaving the chapel, one goes through several chambers, greeting the statue of another famous visitor, Goethe, and passing a small brine lake before reaching gift shops where one can buy salt, health-infused bath salts, and a variety of souvenirs or eat in an under-earth restaurant. One is then quickly whisked back to our polluted earth's surface in a mine elevator, having added a few moments of health to one's life span. So, yes, I would add the salt mine to my list of recommended sites!
Further information:
http://www.krakow-info.com/wielicz.htm
