Tunnels defy landscapes. By design they push away water, burrow through mountains, or simply encase the passenger in a protective shell from the outside. Tunnels provide passage in places that would be otherwise impassable. We searched low, deep, and under for the most impressive tunnels the cut through our world.
1. Marmaray Tunnel, Turkey
Connecting Europe to Asia via tunnel was a nine-year process for the Turkish government. The Marmaray Tunnel—named after the Sea of Marmara that the tunnel runs through (“ray” means “rail” in Turkish)—is 47 miles long with a maximum depth of 180 feet. Opening in 2013, the Marmaray became the longest underwater tunnel in the world and gives Istanbul a new rail line in and out of the city. Crews used the immersed tube strategy to fabricate portions of the tunnel on the surface and then sink them and join them on the seabed instead of crunching through the solid rock of an earthquake zone. Flexible joints made of rubber-reinforced steel plates were designed to absorb any earth movement.
2. Eisenhower Tunnel, Colorado
At 11,013 feet, the Eisenhower is the highest vehicle tunnel in the world, at least according to Colorado’s claims. Traversing the Continental Divide, the Eisenhower Tunnel complex moves through the Arapaho National Forest with two twin bores, both stretching just shy of 1.7 miles and at distances of 115 to 230 feet apart. Opened in the 1970s, the tunnels rise toward the west and at time can approach grades of 7 percent. Each tunnel comes in at 40 feet wide and 48 feet tall, but an exhaust and supply air system located above suspended porcelain enamel paneling in the ceiling creates a different visual for drivers.
3. Gotthard Base Tunnel, Switzerland
We are mere months away from having a new world’s longest and deepest rail tunnel. Construction has been going on for nearly 20 years, but the Gotthard Base Tunnel inside the Swiss Alps finally will open on June 1, 2016, moving rail cars of passengers and freight between Zurich, Switzerland, and Milan, Italy. At 35 miles long and dipping about 7,500 feet below the mountain peaks above it, the Gotthard Base Tunnel eliminates the need for winding mountainous routes by offering the first flat-track route through the Alps.
4. Seikan Tunnel, Japan
The current title holder of world’s deepest and longest rail tunnel opened its 34-mile stretch in 1988 to eliminate the tricky storm-filled water passage across Japan’s Tsugaru Strait. The tunnel goes down nearly 800 feet below sea level. The initial 1970s idea of using a tunnel-boring machine didn’t work with the rock here. Instead, crews turned to dynamite to help carve out the needed space to successfully cart passengers from Honshu to Hokkaido.
5. Tunnel of Love, Ukraine
This is no county fair ride. This 1.8-mile-long tree-encapsulated tunnel in the forests of Ukraine serves as a rail tunnel, moving timber to a factory near the town of Kleven. But the industrial run happens only a few times each day. The rest of the time this tunnel is a tourist draw, especially for the romantically inclined looking for a picturesque spot for a wedding proposal or even a simple kiss.
6. Channel Tunnel, United Kingdom/France
Impressive in scope, use, and engineering, the Chunnel stretches 31 miles under the English Channel, connecting the United Kingdom to France with what it actually a total of three tunnels. The six-year project created two 25-foot-wide tunnels for trains that run 365 days per year and reach speeds of nearly 100 miles per hour while a third tunnel exists as an emergency escape tunnel. Intricate systems of piston-operated air ducts and coolant pipes alleviate the pressure of the trains and the heat of the tracks. Traveling for 23 miles under the English Channel, the tunnel is one of the longest undersea passageways in the world, dipping to depths of 246 feet below the seabed.
7. Bund Sightseeing Tunnel, China
Forget crazy engineering, historical significance, or world records. The Bund Sightseeing Tunnel in Shanghai has none of that. What is has is a dazzling view unlike any other tunnel on the list. The Bund Sightseeing Tunnel allows tourists to cross the Huangpu River in a 2,000-foot visually arresting experience with psychedelic lighting and blaring music.
8. Large Hadron Collider, France/Switzerland
At 17 miles in circumference and buried 570 feet below the France-Switzerland border, the Large Hardon Collider is a ring, not a tunnel from A to B. The enormous tunnel is a marvel of engineering in its own right, with engineers having to make everything absolutley perfect despite working deep under the Alps. Oh, and then there’s that thing about discovering the Higgs Boson, one of the most important physics moments of the 21st century.
9. Zion-Mount Carmel Tunnel, Utah
A century ago, the United States wanted to make its national parks more accessible—not an easy proposition back then for the parks in remote areas. To allow for direct access to Bryce Canyon and the Grand Canyon from Zion National Park, workers built a 24-mile-long highway through Zion, which includes the 1.1 mile Zion-Mount Carmel Tunnel, opened in July 1930 as the longest tunnel of its type in the country at the time.
It wasn’t easy. Working in relatively soft sandstone, workers decided to create windows in the sides of the cliffs to remove the stone as they went. The softness also has required concrete reinforcement and a full-time electronic monitoring system that would alert park officials to any shift in the stone. Nowadays the tunnel is too small to handle two-way traffic of our oversized modern vehicles, so the typically one-way tunnel is managed during heavy tourist times, sometimes requiring long waits to enter.
10. Tokyo Bay Aqua Line, Japan
Instead of having drivers travel around Tokyo Bay in a 60-mile journey to connect the two industrial centers in the cities of Kawasaki and Kisarazu, the government built an 8.6-mile long bridge-tunnel hybrid, the Tokyo Bay Aqua Line, in 1997. A bridge runs to the manmade Umihotaru Island (yes, this tunnel has its own manmade island), where the roadway transitions into a tunnel that continues for the next six miles about 200 feet under the water.
11. Yerba Buena Island Tunnel, California
At 76 feet wide and 58 feet high, the Yerba Buena Island Tunnel is the world’s widest single-bore tunnel, and has been since it opened in 1936. Located on an island in the San Francisco Bay, the tunnel connects the two spans of the San Francisco-Oakland Bay Bridge. The roadways through Yerba Buena are double-decker, with five lanes on each level.
12. Hezekiah’s Tunnel, Israel
Excavated during the reign of King Hezekiah in the 8th century B.C., this aqueduct was constructed to ensure fresh water into Jerusalem even during attack. At about 1,750-feet-long, the rock waterway under the City of David leads to Gihon, a natural spring that provides the water. With such history (read: age) attached to Hezekiah’s Tunnel, expect plenty of tight spaces and directional changes.
13. Jungfraujoch, Switzerland
Getting to the very top of Europe by rail has been a tunnel-filled experience for more than 100 years. Jungfrujoch, Europe’s highest-altitude railway station at more than 11,300 feet, required decades-long construction through the rock, ice, and snow of the Bernese Alps in Switzerland. To reach Jungfraubahn via train, visitors board in Interlaken and then travel 4.3 miles in a tunnel—there are additional sections of just over a mile not in a tunnel—”hewn in the rock of the Eiger and Monch.” Along the way, the train makes stops at intermediate stations at Eigerwand (Eiger Wall) and Eismeer (Sea of Ice) for five minutes each before reaching Jungfrjoch. In all, the train spends about 50 minutes climbing 4,600 feet.
14. Guoliang Tunnel Road, China
Desiring a better way to access the village of Guoliang in eastern China, a five-year project in the 1970s created a tunnel road that squeezes through the rocky cliffs for about three-quarters of a mile. At about 15 feet high and 12 feet wide, don’t expect much wriggle room. Along the route there are more than 20 openings that expose the roadway to the cliffside, which also allowed for easy discarding of excavated rock during construction. Those holes also subject drivers to looking at the hundreds of feet of cliff drop from the side of the Taihang Mountains that’s right next to you.
15. Sequoia National Park Tree Tunnel, California
Not every impressive tunnel is for cars and trucks, especially when one lets you traipse through some of our world’s largest trees. Created as a tourist attraction back when our National Park Service focused more on bringing tourists to town than preserving nature at all costs, there’s a tunnel through a tree in Sequoia National Park large enough that people can walk through. Nearby, another tunnel cut through a 275-foot-tall sequoia that fell across Crescent Meadow Road in 1937 is big enough for car passage.
16. Thames Tunnel, London
With horse and carriage the popular mode of transpiration in the early 19th century and boat traffic on the River Thames ever increasing, London needed a novel way to cross the water. They turned to digging under the river. The city mounted some failed attempts in the soggy soil mounted before an engineer developed a cast-iron tunnel shield. Even so, digging under the river led to five tunnel floods, six deaths, and a seven-year abandonment during the 18-year construction process. The Thames Tunnel may not be able to match the technological prowess of more modern version but it was the world’s first tunnel under a river, a hugely important feat.
17. Laerdal Tunnel, Norway
The world’s longest road tunnel opened in 2000 connecting Oslo and Bergen. Instead of trekking through narrow mountain passes often drowning in snow, cars can now travel through this 15.2-mile connection that has an extensive ventilation system to clear the long passageway of polluting car exhaust. Another key attraction: the lights. To break up the monotony of a 20-minute tunnel ride, designers used white lights through the main portion of the tunnel and then built in three “caves,” with blue and yellow lights mimicking sunrises. These areas offer drivers a psychological lift, as well as a place to turn around.
18. Natural Tunnel, Virginia
Sometimes nature creates its own passageways, as in the case of the Natural Tunnel in the Appalachian Mountains of southwest Virginia. Carved over time by the carbonic acid in groundwater and Stock Creek eating away the bedrock, the Natural Tunnel now runs 850 feet in length with sections as high as 100 feet, giving it the look of human invention. While nature made the tunnel, humans did take over, lying rail track inside the tunnel for passenger service in the late 1800s. The lines are still active today carrying freight.