On July 17, 2001, Sicily’s Mount Etna blew. Again. During the largest eruption in nearly a decade, Europe’s highest (11,000 feet) and most active volcano spewed some 65 million cubic yards of lava and ash. At dawn August 1, as photographer Art Wolfe reached the summit to shoot the flank eruptions below, he heard a sound "like a jet engine roaring out of the earth" as he caught the sun’s illumination of the plume. Surprisingly, the eruption was over by August 10. But for how long? Ah, that’s the question. Mount Etna’s record reveals an unpredictable pattern, so the grand show could begin again at any time.