Svartifoss in Sveitarfélagið Hornafjörður

You're standing at Svartifoss, the Black Waterfall, in Skaftafell, part of Vatnajökull National Park in the south of Iceland. It's one of the most popular sights in the park, and once you take a proper look, you can see why. The water doesn't fall over ordinary rock. It drops past a wall of dark, perfectly straight columns, and those dark columns gave the waterfall its name.