Tourists in southern Argentina witnessed a breathtaking natural phenomenon when huge chunks of the Perito Moreno Glacier broke off in front of them.

Pieces of ice crashed into Lake Argentina, prompting cheers from onlookers at Los Glaciares National Park.

The massive natural monument in the province of Santa Cruz measures about 100 square miles and its walls tower about 75 yards over water level.

Periodically the glacier advances over the lake and then breaks off.

The glacier last broke apart in March 2012.