RESIDENTS of Hawaii’s Big Island are on high alert for a possible massive eruption of the Kilauea volcano after the USGS recorded 250 earthquakes in just 24 hours. But where exactly is Mount Kilauea?

POPOCATÉPETL VOLCANO, Mexico — In the predawn darkness, a team of scientists climbs the slope of Mexico's Popocatépetl volcano, one of the world's most active and whose eruption could affect millions ...