Norway is currently blasting through solid rock underneath the Atlantic ocean bed to create the longest and deepest undersea road tunnel ever built.
It's called the Rogfast tunnel, or the Boknafjord tunnel. When workers finish digging, the route will stretch nearly 27 kilometers beneath the fjords of western Norway, dropping down to a maximum depth of 392 meters below sea level. To give you some perspective, that's deep enough to bury the Empire State Building under the ocean floor with room to spare.
The project comes with a price tag of around 25 billion Norwegian kroner (roughly £1.8 billion). But why would a nation of under six million people invest billions to build a massive mega-tunnel through hazardous, leaking granite?
The answer lies in how Norwegians actually move across their own country.
The Nightmare of Highway E39
If you want to drive from Kristiansand in southern Norway up to Trondheim in the north along European route E39, you're in for a rough journey. The 1,100-kilometer drive takes roughly 21 hours.
Why so long? Because the coastline is carved up by hundreds of deep fjords. Drivers currently have to board seven different ferries along the route.
Miss a ferry by two minutes? You're sitting in a parking lot for an hour. Bad weather rolls in? The ferry stops running entirely. Truck drivers carrying fresh salmon or industrial equipment face constant delays, which drives up logistics costs across the whole Scandinavian economy.
The Norwegian Public Roads Administration, known as Statens Vegvesen, wants to eliminate all ferry connections along the E39 by 2050. Rogfast is the flagship project designed to make that dream happen. By replacing the long ferry cross across Boknafjord, the tunnel will cut travel time between the major coastal cities of Stavanger and Bergen by 40 minutes in one single leap.
Drilling Through Crushed Rock and Leaking Seawater
Most major subsea tunnels in Europe, like the Fehmarn Belt tunnel being built between Denmark and Germany, use pre-cast concrete sections lowered onto the sea bed. Norway isn't doing that.
Norwegian engineering crews use a technique often called the Norwegian Tunneling Method. They literally blast through solid bedrock using heavy explosives and drill rigs, working simultaneously from multiple underground fronts.
That approach brings serious physical challenges.
Down at 300 meters below sea level, water pressure is intense. Ocean water constantly tries to find fractures in the rock and flood the working shafts. Crews have to drill test holes 15 to 20 meters ahead of each section. If they hit water or soft, unstable geology, they pump a thick concrete grout slurry under high pressure into the surrounding rock to seal the cracks before blasting.
The rock quality changes constantly too. In one stretch, workers drill through rock hard enough to hold itself up with simple steel bolts. A few meters later, they hit soft fault zones crushed by millions of years of tectonic movement, requiring thick reinforced concrete arches across the ceiling.
Work crews work 12-hour shifts underground for 12 days straight, followed by 16 days off on the surface. Each blast moves the tunnel forward by about five meters.
An Underground Roundabout 260 Meters Below the Surface
The main tunnel consists of two parallel tubes, each carrying two lanes of traffic. But the engineering gets even weirder about halfway through.
Engineers are building a massive subterranean junction connected to Kvitsøy, an isolated island group that happens to be Norway's smallest municipality. To make this junction work, construction teams are constructing two full-sized traffic roundabouts roughly 260 meters beneath the surface of the sea.
This underground interchange allows traffic to switch direction or exit toward Kvitsøy without stopping. It also gives emergency teams options to reroute traffic into the opposite tunnel shaft if an accident or fire occurs.
Combatting Tunnel Fatigue with Art and Underground Halls
Driving nearly 27 kilometers through a dark concrete tube is a psychological nightmare for many people. Tunnel anxiety and driver hypnosis are real safety concerns on long underground drives.
To break up the monotony, architects designed several cavernous underground halls along the route.
These halls feature special colored lighting installations that illuminate the raw rock walls, creating a vibrant visual break from standard tunnel driving. The visual reset helps drivers stay alert, gauge how far along they are, and keep their focus sharp for the rest of the drive.
What Happens to 8.5 Million Cubic Meters of Dug-Up Rock
Blasting a 27-kilometer subsea tunnel leaves you with a massive pile of rubble—around 8.5 million cubic meters of crushed stone.
Instead of trucking all that stone across the country, Norway is using the rock to build brand new land. Portions of the excavated stone are being used to construct artificial land masses and shoreline extensions in Randaberg and Bokn, creating useful industrial space out of ocean water.
Cost Overruns and the Long Road to 2033
A project this extreme rarely goes off without a hitch.
Work originally started back in 2018. However, after initial bids came back dramatically higher than expected, the government halted the project in 2019 to overhaul the budget and tender structure.
After restructuring the contract terms into smaller, more manageable packages, major construction resumed in 2021 with major Scandinavian builders like Skanska and Implenia taking on the heavy lifting. The total project cost swelled to roughly 25 billion kroner, funded by a mix of state support and future toll revenues.
Current schedules put the official opening around 2033. When the ribbons are finally cut, drivers will cruise beneath the ocean floor on one of the most audacious pieces of transport infrastructure ever built.
To stay updated on the project's progress, you can track official construction updates directly on the Statens Vegvesen website.
