Indonesia is one of the most volcanically active regions of the world. Forming part of the Pacific ‘Ring of Fire’, numerous volcanoes frequently and violently erupt, spewing ash, pumice, blocks and bombs across the archipelago.

Ash can travel great distances (sometimes over hundreds to thousands of kilometres), blanketing the landscape and forming a discrete single layer that marks the point in time when the eruption took place. Some of these layers are often found covering fossil remains.

Gunung Batur on Bali is a huge caldera that has a long history of explosions, last erupting in 1917. Some of these eruptions may have directly impacted on ancient human populations; driving evolution and migration in the region. In the background of this movie, the holy volcano of Gungung Agung is also shown; this last erupted in 1963.