Mount Pinatubo 1991 Eruption — The summit caldera as seen on Aug. 1, 1991 Photo Credit: By Photo by T. J. Casadevall, U.S. Geological Survey. - http://www.ngdc.noaa.gov/hazardimages/picture/show/690, Public Domain, https://commons.wikimedia.org/w/index.php?curid=620012
