The underground salt kingdom that became one of Europe’s strangest attractions

By Sadie Andrew, CNN

Wieliczka, Poland (CNN) — Down at the bottom of 380 dizzying steps, the walls are an imperfect gray. They look like rock — but they taste salty. How do visitors know? They’re encouraged to lick them.

Just to the southeast of Krakow, Poland’s second-largest city, lies the underground realm of the Wieliczka Salt Mine — part cathedral, part industrial relic, part theme park.

Every day, up to 9,000 visitors descend into the mine, which was declared a UNESCO World Heritage Site in 1978. Salt production at Wieliczka ended in 1996. But after 700 years of operation, and more than 150 miles of tunnels chiseled underground, it lives on as a tourist attraction.

Over the centuries, miners at Wieliczka created nine levels of tunnels and chambers reaching 1,073 feet — nearly 330 meters — below the surface. Today, around 2% of what they created remains open to the public. Even that fraction is impressive.

Accompanied by guides, visitors can walk the classic tourist route — just over two miles in about two hours — or opt for the “miners’ route.” On the three-hour adventure, they’re given a headlamp, helmet and emergency carbon monoxide absorber.

The tourist route begins with the descent down those 380 steps — or a ride in an elevator. Labyrinthine passageways lead to preserved chambers hollowed out from the rock by hand. Today, they’re filled with statues, carvings and grand chandeliers that trace the mine’s history and offer insight into the lives of those who worked there. The tourist route ends at the third underground level, 450 feet below ground. The miners’ route runs between depths of 187 and 330 feet.

The salt walls are not white because the sodium choride is not pure, explains tour guide Patrycja Antoniak, as she exhorts her visitors to lick the surfaces. “Not there,” she warns, cueing up a big “ewwww!” moment. “Many people lick there.”

“Ninety to ninety-five percent of the rock is salt — sodium chloride — and impurities give the salt the gray color,” she says. In Wieliczka, the mix includes other minerals as well as sand, silt, and claystone. Despite the color, it’s still edible, Antoniak adds. “It was used to preserve food without being purified.”

Halite, the proper name for rock salt, forms when ancient bodies of water evaporate. Some deposits are hundreds of millions of years old. The one at Wieliczka is relatively young — about 13.5 million years old.

Tectonic movement in the Carpathian Mountains later pushed the salt layers closer to the surface, making them easier to find. Wieliczka contains both “bedded” or layered deposits and “lump” deposits, where the most ornate chambers are located. Miners chiseled them out inch by inch until 1743, when gunpowder was introduced. Mechanical drills followed about 150 years later.

To prevent collapse, miners left a layer of salt in each chamber. Today, the structures are reinforced with modern engineering, including fiberglass rods inserted into the walls.

A salt mine — and a gold mine

Excavation began in the late 13th century, though salt had long been essential to life here. Prehistoric communities boiled water from briny springs, evaporating it to collect salt that was traded as currency.

As demand grew, wells were dug to access brine, followed by shafts. It was in one of these shafts that the first lumps of rock salt were discovered in the late 1200s.

In the 14th century, the mine became a royal asset under King Casimir III of Poland. Known as Casimir the Great, he recognized salt’s economic power. Revenue from extraction accounted for as much as a third of the royal treasury’s income during his reign — wealth that helped finance Poland’s first university. By the end of the 15th century, Wieliczka was producing between 7,000 and 8,000 tons of salt annually.

Life in the mine was demanding, though not as hazardous as some other forms of mining. “It wasn’t a bad job because of the good air, soft rock and short working day,” says Antoniak. “It wasn’t easy here, but it was easier than in other mines.”

Still, the work was grueling. Excavating a single chamber could take decades, often spanning generations of the same family. Among the most dangerous jobs belonged to the so-called “penitents,” who burned off excess methane in the chambers to prevent explosions.

Conditions were harsher for the horses introduced in the 1500s to power pulleys lifting salt to the surface. Once underground, the animals never saw daylight again. A horse cart still stands in one of the chambers.

The mine took on a darker role during World War II. Under Nazi occupation, it was converted into a subterranean factory producing aircraft components. Forced laborers — prisoners from the nearby Płaszów concentration camp, including many Hungarian Jews — worked there, forbidden from speaking to regular miners. The operation lasted only a few months; humidity and salt proved unsuitable for metalworking.

Though mining has ceased, salt production continues. Water infiltration — dangerous because it dissolves salt and weakens the walls — is pumped to the surface. The brine is evaporated, leaving behind crystals in a process similar to sea salt production. More than 10,000 tons are produced annually.

A tourist attraction for 300 years

Tourism at Wieliczka dates from the early 18th century. Visitors once attended firework displays in the chambers and took boat rides across an underground brine lake. Prominent guests came even earlier, including the Polish astronomer Nicolaus Copernicus, who is believed to have toured the mine in 1493.

“He was the first ‘tourist’ in the mine — the first person who came not to work but to see the miners cutting and transporting salt,” says Antoniak. A salt sculpture of Copernicus was installed in a chamber in 1973.

For many visitors, the highlight is St. Kinga’s Chapel — a vast underground church carved from a former mining chamber. It is dedicated to Kinga, the 13th-century Hungarian princess and patron saint of salt miners.

Legend holds that Kinga asked her father for a dowry of rock salt when she married a Polish duke. After he offered her Hungary’s largest salt mine, she threw her engagement ring down a shaft there. The ring was later said to have been found in Poland, embedded in a lump of salt discovered near Krakow — possibly at Wieliczka.

Carved over 67 years by three miners — Józef Markowski, Tomasz Markowski and Antoni Wyrodek — the chapel was completed in 1964. Mass is still held there on Sundays and special occasions, including weddings. A sweeping staircase leads into the chamber, where biblical scenes are carved into the walls alongside a salt-rock altar and chandeliers made from salt crystals.

Bungee jumping underground

Today, Wieliczka is not just a museum but also an events venue. Two chambers have been fitted with wooden flooring for galas and private functions. One, nearly 120 feet high, has hosted a bungee jump and even a tethered hot air balloon ride.

There’s also a spa, located 450 feet below ground specializing in respiratory treatments — a subterranean version of modern wellness “salt caves.”

“It’s healthy here, not like in a coal mine where it’s dusty and difficult to breathe,” says Antoniak. “Salt miners don’t suffer from black lung and they live longer than other miners. The air is almost free from bacteria.” Salt’s antiseptic properties and ability to absorb moisture help limit harmful microorganisms.

“The air is saturated with minerals. It’s not polluted with dust, with pollen. It’s good for people with allergies, for example, to breathe here under the ground,” she says.

Though no longer an active mine, Wieliczka still employs hundreds of miners. Maintaining the site is labor-intensive, Antoniak explains. The greatest threat is water, which can weaken the cavern structure.

“Many miners’ jobs is to collect the water and pump it to the surface.
They have to make sure it’s safe so we can let visitors in. So they make sure the wooden constructions are still supporting the ceiling.”

Today, more than 380 miners work to protect the underground complex from water damage and preserve the excavations — custodians of a kingdom carved from salt.

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