The explosion of this triad of volcanoes on August 27, 1883, the culmination of a three-month eruptive phase, astonished the world because of its global impact. Perhaps one of the most influential factors, however, was its timing. It happened during a time of major growth in science, technology, and communications, and the world received current news accompanied by the correspondents' personal observations. The explosion was heard some 3,000 mi (4,828 km) away, on the Island of Rodriguez in the Indian Ocean. The glow of sunsets was so vivid three months later that fire engines were called out in New York City and nearby towns.

Krakatoa (or Krakatau), located in the Sunda Strait between Java and Sumatra, is part of the Indonesian volcanic system, which was formed by the subduction of the Indian Ocean plate under the Asian plate. A similar explosion occurred in A.D. 416, and another major eruption was recorded in...