The Great Lakes aren't all that great, in terms of depth anyway.
At over a mile deep (1,642 meters or 5,387 feet) Lake Baikal in the Russian region of Siberia is the deepest lake in the world. It's also the most voluminous freshwater lake on the planet.
Lake Baikal is a rift lake, which means that it was created when parts of Earth's crust pulled apart and the resulting gap filled with water. Baikal was created more than 25 million years ago, making it also the world's oldest lake, too.
The Baikal Rift Zone is the deepest of its kind with the rift floor between 8 and 11 kilometers (more than 5 miles) below the surface. The 4 miles between the lakebed and the rift floor is filled with sediment.
The next deepest lake is also a rift lake. Located in Africa, Lake Tanganyika is 1.5 kilometers (0.93 miles) deep at its deepest point.