Salt has been one of the most important minerals on Earth for many generations. It is used to preserve foods, make them taste better, and of course, it is required for our survival.

So, it is no surprise that in just about every place where humans have lived over the years, there was some source of salt around, some bigger than others.

In southern Poland, for example, there is a salt mine that has been used for thousands of years. Experts say that the mine was formed about 13.5 million years ago when seawater flooded the area, but after shifts in tectonic plates, the water drained out, leaving massive amounts of salt behind.

When our ancestors lived in the area, they took full advantage of this source of salt, which initially was taken from the salt springs, and then in the 11th and 12th centuries, they began mining for it. The mining continued until 1996, making it one of the oldest salt mines in the world.

While the salt and its history are interesting enough, the real story comes from what is within these salt mines.

The mines boast over 245 kilometers (152 miles) of tunnels that go down nine levels. At the deepest point, they are 327 meters (1072 feet) under ground.

The miners who worked here didn’t just pull the salt out to use or sell, they actually carved things into the hardened salt walls. The most iconic area of the mines is undoubtedly St. Kinga’s Chapel, which is located 101 meters (332 feet) underground. St. Kinga is the patron saint of salt miners, so it is clear where it got its name.

The chapel is largely carved out of salt, including a replica of The Last Supper. More recently, a statue of Pope St. John Paul II was carved out of salt and added to the chapel. JPII being from Poland, it is a wonderful addition.

The room where the chapel is located can accommodate about 400 people. Mass is still celebrated here throughout the year.

This chapel is just the most well known room in the salt mines, but there are many others, and even additional places of worship.

While mining no longer takes place here, it is still a very popular tourist destination, and it is easy to see why.

If you thought that was interesting, you might like to read about 50 amazing finds on Google Earth.