Iceland sits on a ridge where two tectonic plates are slowly pulling apart.

The longer version

Where two plates move away from each other, magma rises to fill the gap and solidifies into new crust. Iceland sits directly on such a boundary, with the ridge crossing the island. Because fresh rock keeps forming, the island is geologically young compared with most continental land. The split runs roughly from southwest to northeast, and the two sides drift apart by a few centimetres each year.

Volcanoes and hot springs are common there, and heat from below is used for warming buildings and generating electricity. Earthquakes occur as the crust cracks along the boundary. The surface also shows fissures and lava fields, making the boundary visible on land in a way that is rare elsewhere, since most such ridges lie deep beneath the sea.

Where this entry sits

These facts wander across maps, borders, deserts, rivers, mountains, and the extreme corners of the natural world. Each one is short and self-contained, offering a small surprise about places you may never visit rather than anything you actually need. The full list sits on the Geography page, where every entry is listed in order.