Aurora borealis over a waterfall in Iceland. This is the Seljalandsfoss waterfall. This waterfall is 60 metres tall, and is part of the Seljalands river that flows from the Eyjafjallajokull glacier. The aurora borealis is a coloured light display (the northern lights) that is visible in the night sky, usually only at high latitudes. It occurs when charged and energetic particles from the Sun (the solar wind) are drawn by Earth's magnetic field to the polar regions. Hundreds of kilometres up, they collide with gas molecules and atoms, causing them to emit light. The Pleiades star cluster is near the horizon just left of centre. The Andromeda galaxy is at upper right. Photographed on 26 October 2019.