A trek to summit of the world-famous volcano Mount Pinatubo, guided by native Aetas.
The birth of modern Mt. Pinatubo occurred in the most explosive eruption in its history, which deposited pyroclastic flow material up to 100 meters thick on all sides of the mountain. The total volume of material erupted may have been up to 25 cubic kilometers (6 mile³), and the removal of this amount of material from the underlying magma chamber led to the formation of a large caldera.
Earlier large eruptions occurred 17,000, 9000, 6000–5000 and 3900–2300 years ago. Each of these eruptions seems to have been very large, ejecting more than 10 km³ of material and covering large parts of the surrounding areas with pyroclastic flow deposits. Scientists estimate that the most recent eruption before 1991 happened about 500 years ago, and after that, the volcano lay dormant. Its slopes became completely covered in dense rainforest, and eroded into gullies and ravines.