Environment Transportation 10 Tremendous Tunnels to Drive Through By Matt Hickman Matt Hickman Writer Emerson College The New School Matt Hickman is an associate editor at The Architect’s Newspaper. His writing has been featured in Curbed, Apartment Therapy, URBAN-X, and more. Learn about our editorial process Updated August 15, 2021 The Laerdal Tunnel in Norway is the longest in the world. TPopova / Getty Images Share Twitter Pinterest Email Environment Active Automotive Aviation Public Transportation Chances are, you've driven through a fair number of tunnels, some short, some long, some spanning underwater, and some cutting through formidable topographic features such as mountains that would require a lengthy detour to get from point A to point B. These claustrophobic-inducing examples of public infrastructure—all staggering feats of engineering—were built for various reasons. While most were constructed to shave time off established land routes or built as alternatives to ferries or bridges, some of these underwater corridors provide the only way in or out of isolated locations. Here, then, are 10 of the world's most singular underground and underwater tunnels. 1 of 10 Anton Anderson Memorial Tunnel (Whittier, Alaska) StellaMc / Getty Images Long, dark, and narrow, a roughly 10-minute jaunt through the Anton Anderson Memorial Tunnel—better known as the Whittier Tunnel—is the best day trip from Anchorage that $13 in tolls can buy. (Tolls are higher for passenger vehicles pulling trailers as wells as for buses or trucks.) At 2.5 miles long, this single-lane roadway slicing through an Alaskan mountain is the longest combined rail/highway tunnel in North America. The tunnel serves as the only overland link between Whittier, Alaska's, roughly 200 residents—who all live under one roof—and the rest of civilization. Traffic, which flows in only one direction at a time, is regulated according to summer and winter schedules published by the Alaska Department of Transportation and Public Facilities. Scheduled and unscheduled trains, which travel along tracks integrated into the concrete roadway, can prompt delays. 2 of 10 Detroit-Windsor Tunnel (Michigan and Ontario, Canada) Walter Bibikow / Getty Images Completed in 1930 as the first and only nation-linking underground vehicle corridor, the Detroit-Windsor Tunnel, built for $23 million, is the third oldest underwater vehicle tunnel in the United States or Canada, behind New York/New Jersey's Hudson River-crossing Holland Tunnel (completed in 1927) and the Posey Tube (completed in 1928), which connects Alameda and Oakland, California. The four-lane Detroit-Windsor Tunnel is also one of the busiest border crossings between the U.S. and Canada. Crossing under the Detroit River 75 feet below the surface at a length that's just under a mile, the tunnel has a ventilation system capable of pumping 1.5 million cubic feet of fresh air into the 85-year-old subaqueous roadway tube each minute. 3 of 10 Eisenhower-Johnson Memorial Tunnel (Colorado) ggraphix / Getty Images The highest vehicular tunnel in the United States with an average elevation of 11,112 feet, the Eisenhower-Johnson Memorial Tunnel—or, simply, the Eisenhower Tunnel—travels through the Continental Divide. Carrying Interstate 70 along a four-lane passage about 50 miles west of Denver, the tunnel spans just under 1.7 miles from portal to portal, carrying over 30,000 vehicles daily. Open 24/7, the tunnel is a shortcut that allows motorists to circumvent the overland route along a particularly windy stretch of U.S. Route 6 through Loveland Pass. While convenient, Rocky Mountain scenery-seekers often opt not to take the tunnel, which knocks a little over 9 miles off their journey compared to the much more scenic overland route. 4 of 10 Lærdal Tunnel (Norway) Perszing1982 / Getty Images Spanning 15 miles across, the Lærdal Tunnel is the longest in the world. Relatively new—it opened in 2000 as a means of eliminating the ferry rides and frequently closed mountain passes associated with traveling from Oslo to Bergen along the E16 Highway—it takes about 20 minutes to travel from one end to the other. The two-lane mountain tunnel features a trio of caves, which also serve as rest areas. Spaced roughly 3 miles apart, these areas allow drivers to take a quick break or turn around and head back the other way. Lærdal is also the first vehicular tunnel in the world to boast its very own air treatment plant. 5 of 10 Mont Blanc Tunnel (France and Italy) constantinopris / Getty Images Heavily trafficked, the 7.2-mile-long Mont Blanc Tunnel was a time-saving route when completed in 1965 and was for over a decade the longest in the world. Whisking traffic between the bustling ski resorts of Chamonix, France, and Courmayeur, Italy, the tunnel is co-managed by both of these countries. On March 24, 1999, a fire broke out on a Belgian cargo truck passing through the tunnel, sparking a blaze that cost 38 people their lives. Following the fire, the tunnel was closed for three years as it was repaired and retrofitted to include numerous new safety features. Today, memorial plaques can be found near both the Italian and French portals. 6 of 10 Mount Baker Tunnel (Seattle) Robert Macdonald / EyeEm / Getty Images Seattle's art deco-tinged Mount Baker Tunnel is actually three separate tunnels: two twin-bore tunnels completed in 1940 and a third tunnel, a double-decked structure with a pedestrian/bicycle pathway completed in 1991. Together, they carry Interstate 90 beneath the hilly southeast Seattle neighborhood of Mount Baker. 7 of 10 SMART Tunnel (Kuala Lumpur, Malaysia) David Boey / Wikimedia Commons / CC BY-SA 4.0 Completed in 2007, Malaysia's SMART Tunnel was designed and built to divert stormwater away from the oft-flooded center of Kuala Lumpur. SMART Tunnel—which stands for "Stormwater Management and Road Tunnel"—is the longest tunnel in Malaysia and the world's longest multipurpose tunnel, but it doesn't handle both traffic along Expressway 38 and floodwater simultaneously. When needed, floodwater is diverted into a longer separate bypass tunnel underneath the 2.5-mile double-deck roadway tunnel. In this scenario, traffic can continue as normal. During heavy, prolonged rains when the threat of extreme flooding is high, the roadway is closed to vehicles, and automated flood control gates are opened so that water can be diverted through both tunnels. 8 of 10 Tokyo Bay Aqua-Line (Japan) Taro Hama @ e-kamakura / Getty Images The Tokyo Bay Aqua-Line is a nearly 9-mile-long bridge-tunnel combination that cuts the commute time between the bustling Japanese prefectures of Kanagawa and Chiba from over 90 minutes to 15. Completed in 1997 following over three decades of planning and construction, it also eliminates the need to travel through traffic-choked Tokyo itself. The nearly 6-mile-long tunnel section is the fourth-longest underwater tunnel in the world and the world's largest underwater road tunnel. The complex is best known for "Umihotaru" (sea firefly), an artificial island-cum-tourist attraction that connects the tunnel with the bridge and includes restaurants, shops, and an observation deck. 9 of 10 Yerba Buena Island Tunnel (San Francisco) Jacob Davies / Wikimedia Commons / CC BY-SA 2.0 More than 200,000 motorists drive through the Yerba Buena Island Tunnel every day. The single-bore tunnel has carried traffic along a double-deck roadway since 1936. Connected by a causeway to the better-known Treasure Island (an artificial landmass built for a world's fair and later used to a naval base), Yerba Buena—formerly Goat Island—is home to a sleepy residential neighborhood of roughly 40 households, a couple of parks, a small U.S. Coast Guard station, a tower, and a historic lighthouse. 10 of 10 Zion-Mount Carmel Tunnel (Zion National Park, Utah) Daniela Rodriguez / Getty Images Spanning 1.1 miles through the middle of a sandstone mountain, the two-lane Zion-Mount Carmel Tunnel is the longest vehicular tunnel in the National Park System. Completed in 1930, the tunnel features a series of galleries—giant windows carved out of the side of the mountain—that provide natural light and fresh air. Larger vehicles are now required to secure a $15 "tunnel permit" that grants drivers of these vehicles permission to pass through the structure. When a permit-holding large vehicle or a parade of large vehicles going in the same direction needs to access the tunnel, park rangers temporarily close it to two-way traffic so that drivers can travel safely through the roadway.