The Perito Moreno glacier in Argentina stretches over a lake. Every few years, the icy connection over the water narrows, forming a distinct bridge. Then it collapses in spectacular fashion. This time the event was caught on camera. You can watch the complete video on YouTube.
Phys.org explains why this event happens:
The phenomenon, which is not linked to climate change, is due to Archimedes's principle, which holds that the buoyant force exerted on a body immersed in fluid is equal to the weight of the fluid displaced, explained Glaciarium, a research center and glacier museum in the Argentine Patagonia region.
"When that force causes the ice to detach from the shore, water begins filtering through and the process of breakdown begins, which is irreversible," said Glaciarium.
-via Gizmodo