Deep beneath Norway’s rugged mountains lies a feat of modern engineering: the L？rdal Tunnel, the longest road tunnel in the world. Stretching an astonishing 24.5 kilometres (15.2 miles) between L？rdal and Aurland in western Norway, this subterranean passage is more than just an infrastructure project, having become a wildly popular tourist attraction.

       Norway is famous for its breathtaking landscapes, from deep fjords and towering peaks to remote villages nestled in valleys. However, these scenic features pose significant challenges for transportation. Before the L？rdal Tunnel opened, travelling between Norway’s capital, Oslo, and its second-largest city, Bergen, required taking ferries or navigating winding, mountainous roads that were often treacherous, especially in winter.

       To solve this problem, the Norwegian government commissioned the tunnel in 1992, and construction began in 1995 under the oversight of the Norwegian Public Roads Administration. The project took nearly five years to complete, with the tunnel officially opening to traffic on November 27, 2000. The total cost was 1.08 billion Norwegian kroner (approximately $113 million; ￡90 million at the time).

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       Excavating a tunnel so long was no small task, and required workers to blast through 2.5 million cubic meters of solid rock, drill from both ends of the tunnel simultaneously, as well as from an intermediate access point, and use advanced ventilation systems to keep the air clean for workers and, later, for travellers.

       Despite Norway’s extensive experience in tunnel construction (the country has over 1,000 road tunnels), the L？rdal Tunnel set new engineering benchmarks, particularly in terms of safety and driver well-being.

       One of the greatest concerns about such a long tunnel was driver fatigue and disorientation. Without proper design, a 24.5-kilometre drive underground could feel monotonous and even dangerous. To address this, engineers incorporated several unique safety features.

       One included cave-like rest areas, where every six kilometres (3.7 miles), the tunnel features large, brightly lit caverns designed to break up the monotony of the drive. These areas are illuminated with blue and yellow lights, mimicking natural daylight and creating a more calming environment. Drivers can also stop and rest here if needed.

       The tunnel has an advanced air purification system that removes dust and pollutants, ensuring that oxygen levels remain high and visibility stays clear. This is crucial in such an enclosed space where exhaust fumes could quickly become dangerous.

       Unlike many long tunnels, L？rdal is completely free to use. There are no tolls, and the tunnel is open 24/7, allowing uninterrupted travel across the country.

       There are also emergency phones and fire extinguishers every 500 meters (1,640 feet), as well as 15 safety cameras monitoring the tunnel, and if an incident occurs, an automated system closes the tunnel immediately to prevent further accidents.

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       The L？rdal Tunnel is an essential part of European Route E16, a major highway that connects Oslo to Bergen. Before the tunnel was built, this journey required navigating steep, often icy roads or taking a ferry across the Sognefjord—the longest and deepest fjord in Norway. The tunnel now allows for a safer and faster drive, reducing travel time significantly.

       This tunnel is also particularly valuable for Norway’s rural communities. Small towns and villages that were once isolated due to harsh weather and poor roads now have year-round access to larger cities, improving trade, tourism, and daily life.

       Despite being underground, the L？rdal Tunnel has become something of a tourist attraction. Many travellers passing through Norway make a special point of driving through it, eager to experience the world's longest road tunnel. The distinctive lighting and cave-like rest areas make it a memorable drive, and for some, it’s a bucket-list experience.

       Additionally, nearby Aurlandsfjord, part of the larger Sognefjord, is home to some of Norway’s most stunning landscapes. Many visitors pair their tunnel drive with a trip to the Stegastein Viewpoint, which offers panoramic views over the fjord, or explore the charming town of Fl？m, known for its famous Fl？m Railway—one of the most scenic train journeys in the world.

       Now over two decades old, the L？rdal Tunnel continues to serve thousands of drivers every day. Norway is currently working on several other major tunnel projects, including the ambitious Rogfast Tunnel, which, at 26.7 kilometres (16.6 miles), will surpass L？rdal to become the longest subsea road tunnel in the world when it opens.