WORLD
Teachers, scroll down for a quick list of key resources in our Teachers’ Toolkit.

Photograph by Luc-Henri Fage, courtesy Wikimedia and Borneo, Memory of the Caves. Public domain.

Map by National Geographic
Discussion Ideas
- The Nat Geo News article outlines threats faced by Borneo’s karst landscape. What is karst? Read through our super-short encyclopedic entry to find out.
- Karst is an area of land made up of limestone. Limestone, also known as chalk or calcium carbonate, is a soft rock that dissolves in water. As rainwater seeps into the limestone, it slowly erodes. As a result, karst landscapes are dotted with sinkholes, caves, and other anomalies.
- What are the leading threats to Borneo’s karst landscape?
- agriculture. Farmers and agribusinesses clear land (often through fire) to establish lucrative oil palm plantations.
- logging. Legal and illegal timber operations harvest fast-growing tropical trees such as beechwood and acacia, which are used in the plywood industry. Clearing land for oil palm plantations also contributes to deforestation in Borneo.
- forest fires. Many fires are intentionally set to clear land for agriculture.
- mining. Operators of legal and illegal quarries extract limestone, primarily for use in cement.
- Why do limestone quarries put karst landscapes particularly at risk?
- Karst landscapes are dotted with caves, underground streams, and sinkholes. Mining in one area could collapse connected regions. “The karst is like a labyrinth—so much could be lost to quarrying,” says Pak Made Kusumajaya, the head of Indonesia’s National Conservation and Museum Agency.
- Why do many scientists think parts of Borneo’s Sangkulirang Peninsula should be a UNESCO World Heritage Site? What features make the region of “outstanding universal value”?
- indigenous culture. It’s home to the Lebbo’, described by Nat Geo News as “the only ethnic group to inhabit this inner part of eastern Borneo.”
- biodiversity. The karst rain forest landscape has been called one of Earth’s “imperiled arks of biodiversity.” It includes:
- blind freshwater fish
- swiftlets and other tropical birds
- orangutans
- a greater diversity of bat species than anywhere else in Southeast Asia
- some of the largest cockroaches in the world
- animals, plants, and fungi still being identified and documented, such as a new species of snail and a new species of gecko
- our human story. According to UNESCO, “The Rock Art of Sangkulirang-Mangkalihat Peninsula, with its thousands of paintings, is an exceptional testimony of the aspects of prehistoric life, the savanna environment and the activities of hunter-gatherer societies in the Kalimantan in prehistoric times.”
- Archaeologists “have found bones and charcoal that date back 35,000 years, the earliest such evidence of human occupation yet found in Kalimantan . . . Along with the old bones they’ve unearthed, [archaeologists have] found hundreds of prehistoric rock paintings that show, in orange to brown hematite pigments, the figures of animals such as tapirs (now extinct on Borneo), banteng (wild cattle), and some creatures unknown to us today.”
- “The caves should be awarded world heritage site status so that the traces of human activities they contain can continue to testify to the history of the region’s human migration. It is this history of migration that has shaped our culture, beliefs, and traditions.”
- water. Five major rivers in East Kalimantan intersect in the region. “The water catchment and storage in this karst is essential to human survival,” says archaeologist Bambang Sugiyanto. “200,000 people who live on the Sangkulirang Peninsula rely on this water.”
TEACHERS’ TOOLKIT
Nat Geo: A Race to Save Ancient Human Secrets in Borneo
Nat Geo: What is karst?
Nat Geo: What is World Heritage?
UNESCO: Sangkulirang – Mangkalihat Karst: Prehistoric rock art area