What is the largest fresh water lake?

Context: Lake Baikal is a rift lake in Russia. It is situated in southern Siberia, between the federal subjects of Irkutsk Oblast to the northwest and the Republic of Buryatia to the southeast. With 23,615.39 km3 of water, Lake Baikal is the world's largest freshwater lake by volume, containing 22–23% of the world's fresh surface water, more than all of the North American Great Lakes combined. It is also the world's deepest lake, with a maximum depth of 1,642 metres, and the world's oldest lake, at 25–30 million years. At 31,722 km2 —slightly larger than Belgium—Lake Baikal is the world's seventh-largest lake by surface area. It is among the world's clearest lakes.

Baikal's age is estimated at 25–30 million years, making it the most ancient lake in geological history. It is unique among large, high-latitude lakes, as its sediments have not been scoured by overriding continental ice sheets. Russian, U.S., and Japanese cooperative studies of deep-drilling core sediments in the 1990s provide a detailed record of climatic variation over the past 6.7 million years.

Answer: Lake Baikal, located in Russia in the southern region of Sibera is the largest and deepest fresh water lake, containing 20% of Earth's fresh surface water.