The origins of Green Hill can be found in Bukit Lawang, a town in North Sumatra close to the Bohorok River. The town is well known for its population of semi-wild orangutans, who were born out of a conservation project and sanctuary and serves as a gateway to the UNESCO-listed Gunung Leuser National Park.

I discovered that even after the orangutan rehabilitation clinic closed in 2002, the orangutans continued to live in the nearby forest and were the primary attraction in Bukit Lawang. Unsavory practices, such as feeding the monkeys so tourists may take photos with them, have grown commonplace because the economy depends on sightings and interactions with orangutans to draw tourists.