Dotted across the globe are some of the most unusual tunnels that you could ever imagine, from one being mysteriously made by giant sloths to another that has been labelled an ‘entrance to hell’.
Tunnels, big and small, have come a long way since the first was thought to have been built in 2200 B.C., which connected the temple of Belos in Babilonia. Then came the first-ever underwater tunnel, the Thames Tunnel, which took a whopping 18 years to build and was opened to the public in 1843. Designed by Marc Brunel and his son Isambard, it connects Rotherhithe and Wapping beneath the River Thames in London.
Since then, tunnels have come on leaps and bounds, with eye-capturing and extravagant masterpieces in breathtaking locations. So much so that we can’t help but marvel at the spectacular pathways, roads and passageways that are dotted all over the world. We’ve taken a look at some of the most extraordinary tunnels that will certainly leave you gawking…
Built by sloths
Back in 2009, a Brazilian farmer made the astonishing discovery of a mysterious tunnel carved out of dirt, spanning almost two metres high, two metres wide, and stretching for approximately 15 metres. Unknown to how the tunnel had appeared, further inspection found deep claw marks etched into the walls, and experts later concluded that it was a paleo-burrow constructed by a large animal. According to scientists, the tunnel might have been the work of a colossal creature like a giant ground sloth or armadillo, dating back at least 10,000 years prior to its discovery.
Giant ground sloths, described as “a hamster the size of an elephant,” apparently existed in ancient times. They are believed to have measured roughly four metres in length, were capable of walking on all fours, and had the ability to stand upright. During the same era, giant armadillos – comparable in size to cars – were said to have made extensive tunnels like the one discovered in Brazil.
Underwater
The Faroe Islands, a part of the Kingdom of Denmark, constructed an impressive network of 17 land tunnels and four subsea ones, including the world’s only underwater roundabout, to prevent the region’s notoriously unpredictable weather. These tunnels are vital for both residents and visitors, significantly easing navigation across the archipelago’s 18 islands scattered across the North Atlantic.
Located roughly halfway between Iceland and Scotland, the islands have long depended on these tunnels to deal with their isolation and severe climate. Súsanna Sørensen, marketing manager at Visit Faroe Islands, previously shared, “Though we are 18 islands, we often joke that we defy the fact that we are islands (thanks to the tunnels).” The tunnels connect the capital of the Faroe Islands, Tórshavn, and Runavík.
‘Entrance to hell’
In an unusual turning of events, major ancient tunnels, thought to be the mythic “entrance to the underworld”, were uncovered in Mexico. A team of archaeologists unearthed the collection of tunnels hidden beneath an age-old church, with photos showing a maze of chambers and pathways. The major discovery from the ARX Project, which led the search, also uncovered an old city called Mitla, which means the place of the dead.
This area was linked to Pitao Bezelao, the Zapotec god of death, but faced destruction with the Spanish invasion in the 16th century. A priest later claimed that concealed beneath the city lay “the back door of hell” – otherwise called the opening to the Zapotec underworld. Before this groundbreaking find, the hidden abyss remained just that – hidden behind ancient edifices.
Prime Minister’s protection
Many might not know that beneath the Prime Minister’s home at 10 Downing Street lies miles of bomb-proof tunnels. Intrepid urban explorer Dan, from Exploring With Fighters, ventured into the ominous underground world to catch a glimpse of the tunnels few top politicians have ever seen, despite it being a risky and somewhat unlawful operation.
Reporting back to his YouTube channel (Exploring With Fighters), Dan found heavy steel doors guarding the entrance to the maze of tunnels, as underground trains could be heard rumbling overhead. The steel-reinforced tunnels, located some 200 feet below the streets of London, were dotted with occasional “stalactites” of limescale. There are even rubber seals on the doors to prevent microscopic particles of radioactive fallout from seeping through in the event of a nuclear attack.
Also found in the tunnels by Dan was an old landline telephone exchange built for communication between different parts of the bunker, as well as a kitchen and even a bar. The most remarkable feature is a bowling alley intended for survivors of World War III to use. When the tunnels were in use, No.10 staff would reportedly cycle along them to get from place to place.
Longest purpose-built cycling tunnel
The world’s longest purpose-built cycling tunnel, Fyllingsdalen, runs through Løvstakken mountain in Bergen, Norway and was only opened in April 2023. The ultra-modern tunnel measures 1.8 miles and took four years to build with a cost of £22.8 million. But what makes this tunnel even more unique is its various art installations, colours and lights that fill the underpass. Pedestrians can take a 40-minute walk through the tunnel to admire the work or cyclists can experience the sight in around 10 minutes.
‘Most expensive’
The Mont Blanc Tunnel, connecting France and Italy, has been labelled “the most expensive” toll tunnel in Europe. The tunnel stretches 11.611 km (7.215 miles) and can set drivers back nearly £50 to pass through one-way. First opened in 1965, the highway tunnel runs beneath Mont Blanc in the Alps, linking Chamonix in Haute-Savoie, France, with Courmayeur in Aosta Valley, Italy, via the French Route Nationale 205 and the Italian Traforo T1, which serves Geneva and Turin.
This route is one of the main trans-Alpine transport routes and dramatically cuts travel distances, shaving off 30 miles to France and Turin and a whopping 60 miles to Milan. Ingeniously designed in a “V” shape for better ventilation, it was a groundbreaking achievement at its inception, originally outstripping the length of any other highway tunnel of its time.
Slinky
Possibly the most playful tunnel in the world is the Slinky Springs to Fame in Germany. This spiral tunnel-like bridge, made up of a staggering 496 hoops, spans the Rhine-Herne Canal in Oberhausen and was designed by artist Thobias Rehberger. It offers a pathway for pedestrians and cyclists from Oberhausen Castle to leafy Emscher Island and transforms into a vibrant light show at night.