Lida Ajer Cave, in West Sumatra, Indonesia, is the location of remarkable fossils that document the evolution of humans. The cave is known for its palaeontological significance, but its historical record has received considerably less attention. It was first documented in written records by the Dutch palaeoanthropologist Eugène Dubois in the late 1880s. Not finding what he had hoped for, Dubois abandoned his work there and shifted his attention to Java, where he later famously reported the discovery of 'Java Man' (known today as Homo erectus). Specimens from Lida Ajer became the focus of renewed investigations in 1948, when the fossilised remains of modern humans were recognised in Dubois' collection. Later dating of these fossils demonstrated that people occupied the region around 70,000 years ago, making them the world's oldest record of Homo sapiens in rainforest environments. Relics of Dubois' time in the cave are still evident there, including excavation pits and refuse. More recent oral histories and physical objects (e.g. grenade shards) relate to the cave's connections with the military activities of World War II and the birth of modern Indonesia. Abandoned infrastructure for bird's nest harvesting in the cave provides a tangible reminder of rapidly diminishing native species that have been exploited for commercial gain on a global scale. This insignificant-looking hole in the ground has, remarkably, provided major insights into human evolution, human use of speleological resources, and cultural appropriation in historic times.