Follow Steve Backshall as he drops down a sinkhole to explore a series of underground Bornean caves threatened by deforestation and limestone quarrying. The journey may lead to the potential to explore other undiscovered subterranean worlds.
AZPM is a service of the University of Arizona and our broadcast stations are licensed to the Arizona Board of Regents who hold the trademarks for Arizona Public Media and AZPM. We respectfully acknowledge the University of Arizona is on the land and territories of Indigenous peoples.