The lake known for being the largest freshwater lake by volume is Lake Baikal. Located in Siberia, Russia, it holds approximately 20% of the world's unfrozen freshwater. This ancient lake is renowned for its depth, reaching about 5,387 feet (1,642 meters), and its unique biodiversity, housing various endemic species. Lake Baikal is a UNESCO World Heritage site and plays a key role in ecosystems and research on freshwater environments.