Nankai Trough
Microbial life forms thrive even in the Mariana Trench, the deepest spot in the Earth's oceans. Microbes also thrive inside rocks up to below the sea floor under of ocean. Expeditions of the International Ocean Discovery Program found unicellular life in 120°C sediment that is 1.2 km below seafloor in the Nankai Trough subduction zone.