East Kalimantan was once mostly covered by tropical rainforest. In prehistory period, there is limestone cave called "Lubang Jeriji Saléh" located in the Sangkulirang-Mangkalihat Karst in district of Bengalon, East Kutai, believed to contain the oldest figurative art in the world. The cave paintings were first spotted in 1994 by the French explorer . In 2018, a team of scientists investigating the cave, led by Maxime Aubert from Griffith University and Pindi Setiawan from the Bandung Institute of Technology, published a report in the journal "Nature" identifying the paintings as the world's oldest known figurative art. The team had previously investigated cave paintings in the neighbouring island of Sulawesi. In order to date the paintings, the team used dating techniques on the calcium carbonate (limestone) deposits close to them.