Stand beneath towering sequoias, watch geysers erupt on schedule, and look out over canyons carved by millions of years of rushing water.
Yellowstone became the world's very first national park in 1872, decades before the National Park Service itself existed.
Old Faithful is famous for its reliable timing, but Yellowstone's Steamboat Geyser can blast water more than twice as high.
The Colorado River has been slicing through rock for roughly 5 to 6 million years to create the mile-deep Grand Canyon.
California's national parks protect giant sequoias that are thousands of years old and among the largest living things on Earth.
The United States now protects more than 60 official national parks, alongside hundreds of other national monuments and historic sites.
Take the quiz and earn the America Explorer badge for your Explorer Passport. Inspired by Kid Explorers: America's National Parks!