The Jakobshavn Isbræ is among the fastest-moving glaciers in the world. The Jakobshavn is an outlet glacier, one of the few places where the giant Greenland ice sheet can shed ice in the form of gigantic icebergs. Sometimes up to a cubic kilometer breaks off the glacier into the sea in one massive iceberg calving. This timelapse video (60x real-time speed) from glaciologist Mark Fahnestock shows one of these massive calving events. Notice the dark blue ice that surfaces when the iceberg flips over in the ice-choked Ilulissat icefjord.