If you’ve never heard of Silfra, it’s one of the only places in the world where you can dive directly between two tectonic plates - the North American and Eurasian plates - slowly drifting apart year by year. The water precipitated in the era of the Vikings and is now melted glacial ice over a thousand years old, filtered through volcanic rock, making it the clearest water on earth, with visibility reaching up to 100 metres.

It’s a surreal experience - floating weightlessly through narrow rocky corridors - suspended in waters so pure you can drink them straight from your regulator - layered in thick drysuits and heavy weights against the near-freezing temperatures, with the coldness somehow sharpening your senses.