Eon (1985)

An enormous hollowed asteroid contains landscapes and evidence of a civilisation connected disturbingly to humanity's future. Bear uses the explorers' movement through its chambers to make apparent boundaries unstable: the structure holds more than the expedition's first measurements can comfortably explain. The scale keeps widening while Cold War tensions accompany the visitors inside. Begin the Eon books here for a dense archaeological and mathematical mystery, with a deliberately enormous imaginative leap beyond the initial artefact.