Yellowstone National Park sprawls over an astonishing 2.2 million acres of wild landscape.

Glacier National Park is home to pristine forests, alpine meadows, rugged mountains, and spectacular lakes.

Mammoth Cave National Park is home to the world's longest known cave system.

Big Bend National Park spans over 801,000 acres in West Texas with diverse wildlife and stunning natural formations.

Białowieża Forest is one of the last and largest remaining parts of the immense primeval forest that once spread across the European Plain.

Lake Neusiedl is the largest endorheic lake in Central Europe, straddling the Austrian-Hungarian border.

Doñana National Park is a natural reserve in Andalusia, Spain.

Denali National Park and Preserve encompasses 6 million acres of Alaska's interior wilderness.

The Nilgiri Biosphere Reserve is an International Biosphere Reserve in the Western Ghats and Nilgiri Hills ranges of South India.

Isle Royale National Park is a remote island cluster in Lake Superior and the home for various wildlife like wolves and moose.