Since antiquity, human beings have been fascinated with caves. In prehistoric times, the earliest Homo sapiens turned caves into rather primitive abodes; over history, caves have also served a variety of purposes ranging from fortresses to wine cellars. Today’s tourists visit caves to discover the vast subterranean wonderlands beneath the Earth’s surface, several of which are home to some of the largest and most spectacular crystalline formations on the planet.

Cueva de los Cristales (Giant Crystal Cave), Naica Mine, Chihuahua, Mexico
Located in Mexico’s Chihuahua State, the Cueva de los Cristales, or “Giant Crystal Cave”, at the Naica Mine was discovered in 2000. It has quickly become a tourist attraction for those fascinated by its spectacularly large crystals of gypsum, the largest on Earth. These incredible formations measure up to 36 feet in length and weigh some 55 tons, larger than some houses. This attraction is definitely not to be missed.

© Géry Parent

Erlebnisbergwerk Merkers Museum, Wartburgkreis, Germany
Formerly a potash mine, the Erlebnisbergwerk Merkers mining museum in Wartburgkreis, Germany attracts visitors fascinated by its rich industrial heritage and amazing subterranean scenery. This testament to the Third Reich-era mining industry is home to halite, or rock salt, crystals measuring up to 1.1 meters (3.6 feet) in length, much larger than those used for highway ice melt. For tourists who enjoy history with their underground tours, Erlebnisbergwerk Merkers is a must-see.

Crystal Cave at Heineman’s Winery, Put-in-Bay, Ohio
Situated on an island in Lake Erie, Heineman’s Winery in the town of Put-in-Bay, Ohio is mostly known for the incredible subterranean wonderland lying beneath its acres of vineyards. Visitors will be fascinated when they see the walls covered from floor-to-ceiling with dazzling crystals of blueish-tinted celestite, measuring anywhere from eight inches to three feet in length. Although many of the crystals were harvested decades ago to produce fireworks, their removal simply added more space for tourists to meander around the cave, which touts itself as the largest of its kind.

Perticara Mining Museum, Novafeltria, Italy
Another of Europe’s greatest crystal displays can be found at the former Perticara sulfur mine, near the northern Italian village of Novafeltria. At its peak in the early and mid-twentieth century before closing in 1964, the mine is still largely intact as a tourist attraction for those curious about the fascinating sights beneath the Earth’s surface. The adjacent mining museum is home to some rather large crystalline structures, including a sulfur crystal measuring 25 centimeters (10 inches) long, that have been unearthed and placed on display for visitors’ enjoyment.

Orda Cave, Orda, Russia
It is no surprise that the Russian Federation, the largest country in the world by area, is home to the longest underwater cave system on the planet. Located in Russia’s Ural Mountains near the town of Orda, the Orda Cave is a true wonder of the natural world. Divers traverse the cave for a glimpse of its stunning gypsum crystals. The presence of said crystals lends the surrounding waters a brilliant transparency that is ideal for photographic expeditions. Although all divers with the proper equipment are encouraged to visit the cave, visitors should best take heed. Water temperatures average a chilly -3°C (26.6°F). For better or for worse, exploring Orda Cave is not an activity for the faint of heart.

— — —

Cover photo © Julian Fong