23,670 years ago, the eruption of Mount Batur created a vast and deep crater lake near the center of Bali, laying the foundation for Balinese civilization. The eruption released enormous clouds of volcanic ash into the sky, which fell to the earth and became a soft black volcanic rock that the Balinese call paras.
Paras rock is light and easy to carve. It became the building block for Balinese architecture, used to construct temples, palaces, courtyards and houses. Paras was also a key ingredient in Bali's famous rice terraces. By 896 AD, tunnel builders were using hand tools to cut irrigation tunnels and canals through the paras to channel water to their rice terraces. These tunnels would sometimes extend for a kilometer or more underground, with some still being built today.
As water flowed down the slopes of the mountain and over the paras rock, it picked up mineral nutrients and delivered them to the rice paddies. This made Bali’s rice harvests the most bountiful in the Malay Archipelago.