Krakatoa, a volcano in the Sunda Strait between the islands of Java and Sumatra, roared the day before the eruption. At about 10:00 a.m., there was a big explosion sending the rock up to seventy kilometers into the air and scattering it over the area of a million square kilometers. The tsunami which accompanied the volcano explosion circled the globe. According to official sources, about forty thousand people were killed in the incident.