Truly a river of ice, Antarctica's relatively fast-moving Byrd Glacier courses through the Transantarctic Mountains at a rate of 0.8 km (0.5 mi) per year. More than 180 km (112 mi) long, the glacier flows down from the polar plateau (left) to the Ross Ice Shelf (right) in this false-color satellite image. Long, sweeping flow lines are crossed in places by much shorter lines, which are deep cracks in the ice called crevasses. The conspicuous red patches indicate areas of exposed rock. The glacier was named for Rear Admiral Byrd, US Navy, who was an Antarctic explorer. Image courtesy of USGS.