St. Michael's Cave – Gibraltar
Although the peninsula of Gibraltar is mainly known for its imposing Rock that towers majestically over the Mediterranean strait before it, beneath the surface, you’ll find a glistening jewel in the form of a fantastic cave, which today is used for various cultural events; a visit will add some extra spice to your stay here. The cave system extends far into the interior of the rock, and local legend has it that these caves connect to the African continent, from where the famous Gibraltarian monkeys are said to have come from. The truth however is that the system ends in a small lake underground, and visitors are only allowed this far into the caves with a local guide. The main sights of St Michael’s Cave, however, are the colourful rocks found here. Created by rainwater slowly seeping through the rock, this slow erosion created long winding passages as well as numerous stalactites and stalagmites that all come in a wide range of colours. Throughout the year, visitors can also experience various plays, ballets and concerts that are held here in the main cave, which has been transformed into a fully functioning venue.
Salt Mines - Wieliczka near Krakow
Just outside Krakow in southern Poland lies the small town of Wieliczka. A quiet, quaint place in the world, it hides something truly spectacular underneath its surface. The region is rich in minerals and salt and for centuries mines were dug to extract these sought after goods. Miners working in these brutal conditions carved out a labyrinth of passages in the salt rocks, not only managing to create a spectacular underground network but also create amazing chambers and halls that today have been opened up to the public to marvel at. The mine is listed as a UNESCO Heritage Site and stretches for to 287km underground. The network includes many interesting features, such as an underground lake, a museum to the history of salt mining (it is more interesting than it sounds) as well as a cathedral where everything, including the lights on the chandeliers, are made out of rock salt. The mine welcomes guests for daily visits, and if you’re in the mood for something truly spectacular, then there are also numerous events taking place here every year, one of which is the annual New Year’s celebration where you can see in a new year deep below the surface of the earth.
Catacombs - Paris
Originally constructed in the late 18th century as a way to accommodate the limited and unsanitary conditions of the Les Innocents cemetery, the Catacombs are today one of the largest burial grounds in the world. Located in underground tunnels that were previously used as limestone quarries, the network of passages was appropriated as an ossuary to contain the bones of perished Parisians. Originally the remains were scattered in a disorganised fashion in the subterranean passageways, but in 1810, Louis-Etienne Hericart de Thury performed extensive renovations that would lay the foundations for the mausoleum that it currently is. Skulls and leg bones where arranged into different patterns, while various stone tablets and arches bearing inscriptions were installed to explain and add further meaning to this underground spectacle. The catacombs have been visited by many people throughout history, including Napoleon III, and during the Second World War parts of it was used by the French resistance movement. Today, after extensive renovation, improved lighting and strengthening of the overall structure of the passages, visitors can once again visit this ghoulish, but fascination sight, right underneath the streets of the otherwise romantic French capital.
Dungeons – Edinburgh, Mary King’s Close
Not exactly an underground site, but more a place where the city built itself over it, Mary King’s Close is today a fascinating experience that will take you into the darker sides of Edinburgh’s history. A labyrinth of narrow streets and tenements that sprung up around the city’s Royal Mile, Mary King’s Close was a place that attracted unsavoury characters and where crime and disease flourished in the squalid conditions. The Close, along with other adjoining streets were closed up in the 18th century after a breakout of bubonic plague in the area, and urban myths and ghastly legends quickly took root in the streets and houses that were being built over by the expanding town. Today, the underground close is being run as the tourist attraction known as The Real Mary King’s Close and found just across from St Giles’ Cathedral on the Royal Mile. Here visitors can explore the dark past of the city, learn about such gruesome tales as the Burke & Hare Murders, the Edinburgh plague as well as the many ghost stories and paranormal activities that lurk in the darkness.
Cenotes – Cancun
With its ancient Mayan pyramids, dense jungle, prehistoric meteor craters and complete lack of rivers running above ground, the Yucatan Peninsula can feel like a totally different place than the rest of Mexico -sometimes it can even feel like it’s not of this world. Fresh water flows in subterranean rivers and emerge only in very distinct sinkholes, known as cenotes. During the time of the Mayans, these deep lake-holes where regarded as sacred sites, where the gift of prophesising would be bestowed upon anyone brave enough to jump from the surface and lucky enough to survive the fall. Today, some of the more famous cenotes have been made safe for visitors to venture into, whether you’re swimming on the surface or diving deep for a true once-in-a-lifetime experience. Explore the awe-inspiring Grutas de Loltun, where remains of prehistoric humans have been found, see the hanging roots of trees at the stunning Ik Kil, take a dip in the clear waters of the Cenote Azul near Chichen Itza, or visit the Cenote Ponderosa, which was used as a sacrificial lake by the Mayans. These are just a few of the many cenotes that exist across the Yucatan Peninsula.