Float in the gap between two continents

Silfra is a flooded crack in the ground at Þingvellir, in the rift where the North American and Eurasian plates are pulling away from each other. What fills it is meltwater off Langjökull that has spent somewhere between thirty and a hundred years working its way underground through porous lava. Lava turns out to be an excellent filter. The water arrives at two degrees, and the far end of the fissure is visible from the near end, more than a hundred meters away.

The morning starts dry, walking down the rift itself with a continent on either side. Then a dry suit goes on over everything already being worn, with a hood and gloves and a short briefing that is mostly about hands.

In the water the sound stops. The fissure is deep and narrow and the float is slow, and there is not much to do except look down at a wall of rock that stays sharp all the way to the bottom. In one stretch it closes in enough to touch both sides at once, which is the photograph everybody comes out with: one arm toward North America, one toward Eurasia. The cold registers on the face, which is the only part a dry suit leaves out, and almost nowhere else.