These are the world's 12 longest tunnels

For centuries, mountains and lakes posed massive problems for engineers.

In both cases, they make travel nearly impossible and can make trips longer by days or months to bypass obstacles.

However, with the invention of Marc Isambard Brunel and Thomas Cochrane’s invention of the tunnelling shield in the 19th century, that all began to change. Tunnels could go deeper – underwater through bedrock – allowing for quicker travel times.

From particle accelerators to portals through Switzerland’s famous Alps, today’s tunnels built with advanced Tunnel Boring Machines make Brunel’s original London Thames tunnel seem tiny by comparison. For the purposes of our roundup, we excluded most metro tunnels, which are often built by cut-and-cover methods instead of boring, and water tunnels, which humans can’t travel through (easily, at least.)

These are the world’s 12 longest tunnels:


12. LEP Tunnel

CERN/LHC/GridPPCERN has announced that the LHCb experiment had revealed the existence of two new baryon subatomic particles.

Location: CERN, Switzerland/France, Europe

Length: 16.6 miles.

Completed: 1988

Perhaps the most interesting tunnel on this list, the Large Electron-Positron collider tunnel is the only one on the list you’d have some trouble trying to travel through. Built in 1988, the tunnel at CERN’s complex on the Franco-Swiss border has been the home to several particle accelerators used by nuclear researchers at the center.


11. London Underground Northern Line

Oli Scarff/Getty Images

Location: London, England (from Morden to East Finchley)

Length: 17.3 miles

Completed: 1940

This portion of the Tube’s Northern Line is still the United Kingdom’s longest railway tunnel. Despite the exclusions of many other metro tunnels on this list, this portion makes the cut because the entire length was bored through solid rock beneath London’s streets.


10. Taihang Tunnel

Location: Tailhang, China

Length: 17.3 miles

Completed: 2007


9. West Qinling Tunnel

CCTV

Location: Gansu, China

Length: 17.5 miles

Completed: 2016


8. Guadarrama Tunnel

Adrian Greeman/Construction Photography/Avalon/Getty ImagesTunnel under construction Entrances for the twin bores of the 20km long Guadarrama tunnels for the new Madrid to Barcelona high speed railway .

Location: Sierra de Guadarrama, Spain

Length: 17.6 miles

Completed: 2007

Spain’s Guadarrama Tunnel carries high-speed trains on the Madrid to Barcelona train line.


7, New Guanjiao Tunnel

Wikimedia Commons

Location: Qinghai,China

Length: 20.3 miles

Completed: 2014

The New Guanjiao tunnel replaced an existing tunnel, built in the 1970’s, through mountains in the rugged Tibetan plateau.


6. Lötschberg Base Tunnel

Wikimedia Commons

Location: Switzerland

Length: 21.5 miles

Completed: 2007

Lötschberg Base Tunnel was formerly the longest in the world until the Gotthard tunnel was completed nearly a decade later.


5. Songshan Lake Tunnel

YouTube

Location: Dongguan, China

Length: 24.17 miles

Completed: 2016


4.Yulhyeon Tunnel

Media Handout

Location: Seoul, South Korea

Length: 31.3 miles

Completed: 2016

South Korea’s Yulhyeon tunnel is virtually tied with the Channel Tunnel, and took more than three years to to carve the shortcut on the Korean peninsula.


3. Channel Tunnel

Location: English Channel, between England and France.

Length: 31.3 miles

Completed: 1994

While the Channel Tunnel has a longer underwater length than Seikan, its total length falls about two miles short of its Japanese counterpart.


2. Seikan Tunnel

Kyodo News via Getty ImagesA Shinkansen bullet train passes through the Seikan Tunnel, the world’s longest undersea tunnel that connects two of Japan’s main islands by rail, in Hakodate, northern Japan on March 12, 2018.

Location: Tsugaru Strait, Japan

Length: 33.5 miles

Completed: 1988

Seikan is the world’s longest tunnel with an underwater segment, beating the Channel Tunnel in total length, but not in terms of how much is under water.


1. Gotthard Base Tunnel

Location: Swiss Alps, Switzerland

Length: 35.4 miles

Completed: 2016

The Gotthard base tunnel is the longest tunnel by distance and also the deepest. Read more about the tunnels history and construction here.

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