The African Great Lakes (Swahili: Maziwa Makuu) are a series of lakes constituting the part of the Rift Valley lakes in and around the East African Rift. They include Lake Victoria, the second largest fresh water lake in the world by area, and Lake Tanganyika, the world's second largest freshwater lake by volume and depth. Collectively, they contain 31,000 km3 (7400 cu mi) of water, which is more than either Lake Baikal or the North American Great Lakes, and constitutes about 25% of the planet's unfrozen surface fresh water.