Wood Buffalo National park is Canada's largest national park (44 807 sq. km) and was established in 1922. The park is found in the plains of north central Canada. Buffalo National Park has been designated a UNESCO World Heritage Site. It is home to the world's largest free-roaming herd of bison and is the sole nesting ground of the whooping crane. While the park encompasses boreal forest as well as some of the largest tracts of undisturbed sedge grasslands, the park's aquatic environments are also prominent. The Peace River flows through the park, while the Slave and Athabasca Rivers form its eastern border. In the southeast corner of the park lies the Peace- Athabasca Delta - one of the largest inland freshwater deltas in the world. The countless streams and wetlands of the delta provide habitat for many waterfowl.