It's an extreme dining experience: 18 feet under the icy sea on the coast of southern Norway.

Restaurant Under, as it's called, opens Thursday. It has a set menu that will rotate seasonally, but expect to see lots of fish and shellfish, plus food from the beach outside like sea arrow grass, sea rocket and salty sea kale. The local area is known for wild mushrooms and berries, and those will be used on the menu as well, according to the restaurant's web site.

PHOTO: Aerial view shows a restaurant named Under, that is semi-submerged beneath the waters of the North Atlantic in Lindesnes near Kristiansand, Oslo, Norway, March 19, 2019.
Erik Schroder/NTB Scanpix/AFP/Getty Images
Aerial view shows a restaurant named Under, that is semi-submerged beneath the waters of the North Atlantic in Lindesnes near Kristiansand, Oslo, Norway, March 19, 2019.

Restaurant Under calls the food's journey from kitchen to plate "minimal."

According to Visit Norway, "Under" in Lindesnes is Europe's first and the world's largest underwater restaurant.

PHOTO: A restaurant named Under, that is semi-submerged beneath the waters of the North Atlantic in Lindesnes near Kristiansand in Oslo, Norway, March 19, 2019.
Erik Schroder/NTB Scanpix/AFP/Getty Images
A restaurant named Under, that is semi-submerged beneath the waters of the North Atlantic in Lindesnes near Kristiansand in Oslo, Norway, March 19, 2019.
PHOTO: Interior view of a restaurant named Under, that is semi-submerged beneath the waters of the North Atlantic in Lindesnes near Kristiansand in Oslo, Norway, March 19, 2019.
Erik Schroder/NTB Scanpix/AFP/Getty Images
Interior view of a restaurant named Under, that is semi-submerged beneath the waters of the North Atlantic in Lindesnes near Kristiansand in Oslo, Norway, March 19, 2019.

An oak staircase descends into the building, where guests can experience the Norwegian coastal ecosystem out the acrylic windows while they dine.

PHOTO: Interior view of a restaurant named Under, that is semi-submerged beneath the waters of the North Atlantic in Lindesnes near Kristiansand in Oslo, Norway, March 19, 2019.
Erik Schroder/NTB Scanpix/AFP/Getty Images
Interior view of a restaurant named Under, that is semi-submerged beneath the waters of the North Atlantic in Lindesnes near Kristiansand in Oslo, Norway, March 19, 2019.

The restaurant will eventually become a part of its marine environment and work as an artificial reef, welcoming marine life to the area.

Under is located about 50 miles from Kristiansand Airport Kjevik, the nearest airport.