Largest Lake by voulme and area:
The Caspian Sea which flows around the Russia, Kazakhstan, Turkmenistan, Azerbaijan and Iran has a voulme of 78,200 cubic km and it covers an area of about 374,000sq km, thus, making it the world's largest lake. It would take 400 years for the entire contents of the Caspian to flow over Niagara Falls!
Largest freshwater lake by volume and deepest lake:
Lake Baikal of Russia contains 22,995 cubic km of water. It has an average depth of 730m and is 1,741m at its deepest point- which is deep enough to cover more than four Empire State Buildings piled of top of one another.
Largest Freshwater lake by area:
The Aral Sea of Kazakhstan and Uzbekistan, once had 64,501 km in the 1960's.
It has now been shrunk to 28,000sq km, since the feeder rivers have been diverted for irrigation and it is now in the danger of disappearing altogether.