One waterfall in Iceland you can walk behind

Iceland has so many waterfalls that you stop counting by day two. But one stands out, not because it is the biggest, but because of what you can do with it. At Seljalandsfoss, on the south coast, you can walk all the way behind the falling water.

It drops around sixty metres off an old sea cliff in a single clean ribbon, and a footpath loops right around the back of it, into the shallow cave the water has carved out behind the curtain. You walk in on one side, stand in the gap between the rock and the falling river, and come out the other. It is loud, it is wet, and it completely rearranges your sense of how close you are allowed to get to something this powerful.

I first saw it from a bus window on my way somewhere else, and even at speed it stopped conversation. Later, driving the Ring Road, we came back and did the full loop behind it. Bring a waterproof, because there is no staying dry, the spray finds everyone. Late evening is the time to go: the low northern sun comes straight through the water and lights the whole thing gold from behind, and the tour crowds have thinned out.

Of all the waterfalls in Iceland, and there are hundreds, this is the one I send people to first. Not because it is the tallest or the most powerful, but because standing behind a waterfall, looking out through it, is the kind of simple, slightly absurd thrill you remember long after the bigger ones blur together.