Niah National Park

Alfred Russel Wallace lived for 8 months at Simunjan District with a mining engineer, Robert Coulson, who had explored what is now northern Sarawak for mineral ores. Coulson later wrote to Wallace about finding bones in a number of caves in Sarawak. On further enquiry, Wallace learned that one cave in question "was situated in the district between Sarawak and Bruni (Brunei), on a mountain some distance inland."