For almost a decade, scientists have joined forces to investigate the lifeforms which inhabit the depths of our planet’s crust – one of the largest and least-explored ecosystems on Earth. Among the mind-boggling discoveries were bizarre creatures that can survive at record depths, pressures and temperatures, and even “zombie” bacteria that may live for millions of years at a time. Researchers claim that they’ve just barely begun to scratch the (sub)surface of the deep biosphere and that there’s plenty left waiting to be discovered.