Ice calving of the Perito Moreno Glacier in Patagonia, Argentina.
Glaciers are constantly in motion, reacting to the pressure from new snow and changing weather, which causes surface cracks, crevasses, and large chunks falling off its face, known as calving . When a glacier as large as the Perito Moreno Glacier calves you hear, for miles, the initial loud shrill cracking sound followed by the deep rumble sound as ice breaks away from the face. You can even feel the change to the water standing on the viewing platforms, as the enormous ice chunks plunge into the green lake exposing the deep blue ice below the ice that has just separated, causing a huge white splash and radiating concentric water ripples. A truly remarkable sight.