Which is largest national park in world?
Northeast Greenland National Park
Northeast Greenland National Park (Greenlandic: Kalaallit Nunaanni nuna eqqissisimatitaq, Danish: Grønlands Nationalpark) is the world's largest national park and the 9th largest protected land area.[1] Established in 1974 and expanded to its present size in 1988, it protects 972,000km2 (375,000sqmi)[2] of the interior and northeastern coast of Greenland and is bigger than all but twenty-nine countries in the world. It was the first national park to be created in the Kingdom of Denmark and remains Greenland's only national park.
Mungo National Park
The national park is part of the UNESCO World Heritagelisted Willandra Lakes Region, an area of that incorporates seventeen dry lakes. The seventeen dry lakes are not all called Mungo but are all declared world heritage. The creek that used to flow into Mungo is being preserved as a sacred site. The national park is about south-east of , north-east of Mildura, Victoria and approximately south-west of . The roads to, in or around the park are unsealed and may become impassable in 2-wheel-drive cars but with care can be navigated in SUVs or 4x4s. 
The central feature of Mungo National Park is Lake Mungo, the second largest of the ancient dry lakes. The Mungo National Park is noted for the archaeological remains discovered in the park. The remains of Mungo Man, the oldest human remains discovered in Australia, and Mungo Lady, the oldest known human to have been ritually cremated, were both discovered within the park. They were buried on the shore of Lake Mungo, beneath the 'Walls of China', a series of lunettes on the South eastern edge of the lake.