Nature
An entire ecosystem was found living without a single ray of sunlight
In 1977, scientists diving in the submersible Alvin to the Galapagos Rift found thriving colonies of giant tube worms, clams and crabs clustered around undersea hydrothermal vents, 2,500 metres down, where sunlight never reaches. Instead of photosynthesis, bacteria there convert chemicals from the vent water into energy, a process called chemosynthesis. It overturned the assumption that all life on Earth ultimately depends on the sun.