El Calafate, Argentina, July 8, 2008—Chunks of ice collapse into the Atlantic Ocean, dramatically splintering from the Perito Moreno glacier in southern Argentina.

The unexpected collapse, documented during the Southern Hemisphere's winter for the first time, is attributed to a very unusual cause—pressure from an advancing glacier.

This Patagonian glacier, a popular UN World Heritage site affectionately called the ''White Giant,'' experienced several days of smaller cracks and breaks prior to Wednesday's rupture, according to the Reuters news service.

• More Photos in the News
• Today's 15 Most Read Stories
• Free Email Newsletter: Focus on Photography