World's longest and deepest road tunnel part of £36 billion project that will help cut 21-hour journey in half

If you happen to be pining for the fjords, then Norway's E39 road is the route you'll be wanting to take.

It's a 21-hour journey from Kristiansand in the south of Norway right up north to Trondheim, but to get there will take a rather stop-start journey that'll require you to hop onto a bunch of ferries.

Cars aren't exactly the best way to navigate the fjords so while it might be an incredible road trip for you to enjoy, it may end up being quite the kerfuffle as you drive on and off a plethora of boats.

The Rogfast tunnel will be the longest and deepest underground tunnel in the world once it's completed. (Statens vegvesen)

However, Norway is embarking on a whopping £36 billion infrastructure project designed to smooth this journey out and cut travel times by half, meaning that you won't even need to get on board a ferry.

Part of the project includes what will be the world's longest and deepest road tunnel once it gets completed, the Rogfast.

The overall plan is to build a series of infrastructure projects along E39 which will eliminate the need for ferry-hopping, and the Rogfast tunnel is the first one someone driving from Kristiansand to Trondheim would make use of.

It'll run beneath the sea between Randaberg and Bokn in Norway's Rogaland county, and this underground road tunnel will be around 17 miles long, which shall make it the longest underground road tunnel anywhere in the world.

At its deepest point it'll be 392 metres below sea level, which is pretty damn impressive.

17 miles long and 392 metres below sea level at its deepest point, this tunnel is part of a £36 billion mega project. (Statens vegvesen)

In fact, Norway has previous in this department as they're currently the world record holders for the longest and deepest road tunnels.

The Lærdal Tunnel was opened in the year 2000 and runs for 15.2 miles in total, and at the time it cost around £90 million.

Meanwhile, the Ryfylke Tunnel is at present the world's longest subsea road tunnel as well as the deepest at 292 metres below sea level, though the Rogfast is due to blow it out of the water once it gets completed.

This tunnel is just one aspect of the £36 billion mega-project which will allow Norwegians to drive up and down their country with much greater ease, and connect many of their cities together.

At the moment, the Rogfast tunnel is scheduled to open in 2033, though back when the tunnel project first got the green light the initial estimations reckoned it'd be done by 2026.

All good things come to those who wait and in less than a decade you could be driving up the Norwegian coastline without having to stop to hop on a ferry.

Just you wait, the Rogfast tunnel is going to be the next big thing in underwater motoring.

At least until someone builds a bigger tunnel.