Glacier Cave

Description

This stunning glacier cave is formed by meltwater rushing out beneath an Icelandic glacier. Most ice caves form at a glacier's edge, where rivers running beneath the ice melt their way out. In winter those rivers slow almost to nothing and the cold stiffens the ice, so the caves are drier and steadier. The blue comes from the ice itself: it absorbs red light, and the farther light travels through it, the bluer it looks.