A glacier in Patagonia, Argentina, calves, with a sudden collapse of ice. Researchers say that the activity that precedes these types of tipping points and the triggers that cause them may follow predictable patterns. Philip Stanley Dickson/iStockphoto.com hide caption

The Freemasons Grand Lodge on 16th Street in Washington, D.C., has served as the national headquarters of the Supreme Council since 1915. Tim Sloan/AFP/Getty Images hide caption

Supporters of ousted and deposed Honduran President Manuel Zelaya march during Independence Day in Tegucigalpa, Honduras, on Tuesday. Zelaya has vowed to return to the country and reclaim his office. Orlando Sierra/AFP/Getty Images hide caption

A smallmouth bass caught on a lake near Ely, Minn. One-third of smallmouths surveyed by the USGS showed signs of intersex. Sam Cook hide caption