Termed as hydrothermal vents as well. Because these habitats are deep and don't receive sunlight, they support some of the most amazing and strange ecosystems on the planet.
The second-biggest barrier reef in the world and the largest in the western hemisphere is the Belize Barrier Reef. There is no beauty like that in the entire globe.
The world's largest freshwater surface water reserve, Lake Baikal is also the deepest lake. It is home to a wide range of indigenous plant and animal species.