Smoke rises from the Grimsvotn volcano, Saturday, May 21, 2011 in Reykjavik, Iceland. Iceland's most active volcano has started erupting, scientists said Saturday _ just over a year after another eruption on the North Atlantic island shut down European air traffic for days. Iceland's Meteorological Office confirmed that an eruption had begun at the Grimsvotn volcano, accompanied by a series of small earthquakes. (AP Photo/Halldora Kristen Unnarsdottir)