These remarkable images show what it is like to swim in the gap where the North American continent separates from its Eurasian counterpart. Taken in the Silfra fissure in southern Iceland, the pictures detail the rip that divides the two tectonic plates, which are drifting apart at a rate of 2 centimetres every year.
Mathieu Foulquié, a marine biologist from France, took the shots at a depth of around 15 metres under Thingvellir Lake. Of his experience he said: “I had the privilege to dive at the famous Silfra dive site, probably the most impressive freshwater rift in Iceland. It is without a doubt a world-class dive site, with one of the clearest freshwaters on Earth. I felt hypnotised by the transparency, and it almost made me dizzy!”
The amazing clear water within the canyon is a consequence of the cold temperatures, along with a natural filtering process that occurs when the water passes through porous lava underground.
Foulquié added: "I did attempt to have a drink whilst diving in the lake, but the water temperature is about 2 or 3 degrees Celsius, and you're already frozen so you don't really need more refreshing. However, because of the lava filtration - which is one of the best in the world - the lake tastes of the purest of waters."
In 2013, underwater photographer Alex Mustard also took a dive at Silfra and three other canyons, to document the place where "the earth is ripping apart." Here are his pictures: