Mount Pinatubo is an active stratovolcano located on the island of Luzon in the Philippines, at the intersection of the borders of
the provinces of Zambales, Tarlac, and Pampanga. Ancestral Pinatubo was a stratovolcano made of andesite and dacite. Before 1991, the mountain was inconspicuous and heavily eroded. It was covered in dense forest which supported a population of several thousand indigenous people, the Aeta, who had fled to the mountains from the lowlands when the Spanish conquered the Philippines in 1565.
The volcano's eruption in June 1991 produced the second largest terrestrial eruption of the 20th century.