Divers describe 'incredible' plunge into icy corridor between two continents in Iceland

Visibility can top 100 metres in the crystal-clear, bone-chilling waters

An aerial view shows snorkellers in the main Silfra fissure which is approximately 300 meters long, on July 26, 2022 in Thingvellir, Iceland. - In between North American and Eurasian tectonic plates, Iceland's Silfra fissure is one of the world's most famous dive sites, popular with tourists who venture into its icy waters. (Photo by Jeremie RICHARD / AFP) / TO GO WITH AFP STORY BY JEREMIE RICHARD

Snorkellers brave the continental crack of Silfra. Photo: Tobias Friedrich Schnorchler

An underwater ravine in the Silfra fissure in Thingvellir. Photo: Jennifer de Winter / AFP

Snorkellers swim in the main Silfra fissure. Photo: Jeremie Richard / AFP

Dry suits and snorkelling equipment are needed to brave the sub-zero temperatures. Photo: Jeremie Richard / AFP

This handout picture taken underwater shows a snorkeller observing the fissure underwater on July 26, 2022 in Thingvellir, Iceland. - Located between the North American and Eurasian tectonic plates, at the bend of two continents, the Silfra Rift in Iceland is one of the most famous dive sites in the world, popular with tourists who venture into its icy waters every summer. (Photo by Thomas GOV / DIVE. IS / AFP) / RESTRICTED TO EDITORIAL USE - MANDATORY CREDIT "AFP PHOTO /Thomas GOV/DIVE. IS " - NO MARKETING - NO ADVERTISING CAMPAIGNS - DISTRIBUTED AS A SERVICE TO CLIENTS

Algae on rocks shimmers phosphorescent green in the Silfra Rift. Photo: Jennifer de Winter / AFP

A diving instructor gives instructions before tourists plunge into the icy waters. Photo: Jeremie Richard / AFP

Diving instructor Lorenzo (R) helps a Canadian tourist (L) to put on her hood before a snorkelling tour on July 26, 2022 in Thingvellir, Iceland. - In between North American and Eurasian tectonic plates, Iceland's Silfra fissure is one of the world's most famous dive sites, popular with tourists who venture into its icy waters. (Photo by Jeremie RICHARD / AFP) / TO GO WITH AFP STORY BY JEREMIE RICHARD

The main Silfra fissure is around 300 metres in length. Photo: Jeremie Richard / AFP

In between the North American and Eurasian tectonic plates, Silfra fissure in Iceland is one of the world's most famous dive sites, popular with tourists who venture into its icy waters.

Visibility underwater can exceed 100 metres and the spectacle of light and darkness is hypnotic.

"When we entered the water, it was ..." says Icelandic tourist Brynjolfur Bragason before pausing.

"Incredible," adds his wife Hildur Orradottir.

In the heart of Thingvellir National Park, on the edge of one of the largest lakes in Iceland, corridors of submerged rocks form deep cavities in between the two continents, which move away from each other by about two centimetres every year.

The orange reflections are mixed with various shades of blue in the more than 60-metre-deep rift, located in the southwestern part of the Atlantic island.

The beige sand and the phosphorescent green of the algae add to the colours.

"It looks like hair," says Camille Lund, a French-American tourist.

'Tingling' feeling

The fissure and the entire surrounding valley lie on the Mid-Atlantic Ridge, which runs through the island, making it one of the most active volcanic areas on Earth.

Silfra was formed by an earthquake more than two centuries ago as a result of a tectonic drift and the clear waters come from the nearby Langjokull glacier, the second largest ice cap in the country.

Water travels for several decades through a tunnel of underground aquifers around 50 kilometres long.

"This whole filtration system through the volcanic rocks ... gives us super-clear water," Thomas Gov, a diving instructor from Toulouse in the south of France, told AFP.

Taking a dip in Silfra requires a lot of preparation as well as a dry suit, diving gloves, swimming hat, mask, snorkel and fins.

The equipment allows swimmers to stay dry and float peacefully on the surface in water, which stays between 2°C and 3°C all year round.

Only part of the face and hands are exposed to the icy water.

"You can feel it in your lips right away: they go numb after a while and they are like tingling," says New Yorker Ian Zavatti, 13, standing next to his father.

Snorkelling is the most popular activity, but the more experienced and certified can dive with a scuba tank to a depth of 18 metres.