A tunnel is typically an underground passageway, built in an effort to address the growing needs of roads, highways and bridges to handle a large volume of traffic. The exact definition of a tunnel has been twitched many times in the past. Irrespective of that, tunnels are the results accomplished by a magnificent feat of engineering, with boring giant holes in mountains, or laying several feet of pathway under the ocean. Let us have a look at the world’s strangest tunnels-

Channel Tunnel

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Channel Tunnel: Located in Coquelles, France, this tunnel is commonly known as the Chunnel. This 31 mile tunnel that links England and France was built in 1994 with a staggering cost of more than $20 billion. The idea of linking England and France through the English Channel was being toyed at for several years. However, the project could not take shape owing to a variety of reasons, technical and political included. The invention of modern boring machines coupled with the irrefutable benefit of linking the two countries finally made it possible. In order to provide protection from fire hazards, designers have built a smaller service tunnel in between the teo main tubes to act as an escape passage.

Smuggling Tunnel

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Smuggling Tunnel: Located in Tijuana, Mexico, this 1000 feet long tunnel was recently unearthed by U.S. and Mexican officials. Tunnels used by slick criminals to smuggle contrabands is not unheard of in the past. During recent years, a large number of illegal tunnels have been discovered in the U.S., coming from Canada and Mexico. This tunnel digs 860 feet into the U.S. The incomplete tunnel was fitted with lighting, a ventilation system, electricity and even an elevator. The Drug Enforcement Agency in U.S. issued a statement saying that the construction of this tunnel has been going on for over two years.

Infiltration Tunnels

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Infiltration Tunnels: In the 1970s, three different tunnels were discovered along one of the most disputative borders of the world. In 1990, a fourth tunnel was discovered creeping under Korea’s Demilitarized zone. The third invasion tunnel, also known as the Third Tunnel of Aggression, came dangerously close to just 26 miles of Seoul, the capital city of South Korea. These secret tunnels gave North Korea a huge advantage of launching a massive military against its strong enemy South Korea. The tunnels were large enough to shuttle an entire military division per hour.

Cu Chi Tunnel

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Cu Chu Tunnel: Situated in Cu Chi, Vietnam, this giant labyrinth of tunnels played an important role during the French Indochina War and the Vietnam War. The size of these tunnels range from 75 miles to over 150 miles. The Cu Chi tunnels have been a popular tourist destination in recent years, enabling visitors to travel through the cramped spaces, check out deadly booby traps and even travel to an underground command center from where the Tet offensive was planned. Tunnel size varies from a few feet tall to larger ones refashioned for accommodating larger tourists.

Tokyo Bay Aqua-line

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Tokyo Bay Aqua-line: This tunnel is located in Kawasaki city, Japan. The tunnel is 6 miles long with a 3 miles long bridge dipping into it. Traffic was permitted to commute in 1997, enabling travelers between Kawasaki city and Kisarazu City to save roughly 45 minutes each day. The unique thing about this bridge-and-tunnel combination is that a large rest area lies on top of an artificial tunnel constructed at the entrance of this tunnel. The island is called Umi-Hotaru, meaning “firefly of the sea”, and serves primarily as a rest area consisting of shops and restaurants, along with an observation deck that looks out on to the bay.