Muir fought to protect Yosemite and later Glacier Bay in Alaska, Mount Rainier in Washington and the Grand Canyon and the Petrified Forest in Arizona.

BBC: Birth and spread of the world��s national parks

The Network includes sites as diverse as Lagkawi Island, featuring the oldest rock formations in Malaysia, the petrified forest on Lesvos Island (Greece) and the volcanic craters of Vulkaneifel in Germany.

UNESCO: NATURAL SCIENCES

From that commitment sprang an effort to save the great Redwoods of California and the Petrified Forest of Arizona, the great bird rocks of the Aleutian Islands and the Tongass of Alaska.

WHITEHOUSE: Presidential Proclamation -- National Park Week, 2012