It looks like something out of a movie, but is very much real life: you're looking at the Aurora Borealis as they illuminate a huge cave in Iceland. It's pretty humbling.
The image was captured by photographer Ingólfur Bjargmundsson, from within the 1360-metre-long lava cave. The people in shot aren't standing on rock: those are actually snow pedestals, that build up as snow falls through the skylights in the cave, where its roof has collapsed. The photo is on the shortlist for the Astronomy Photographer of the Year award at the Royal Observatory Greenwich in London. The winners will be announced on 18 September. [Astronomy Photographer of the Year via New Scientist]