The 20 most-visited national parks in the U.S.

America's 58 national parks feature some of the country's most amazing views, natural formations and wildlife. These include Yellowstone's world-famous geysers, Olympic's rain forests in Washington and Arches' sweeping rock formations in Utah.

Each year, millions travel to these parks. Here are the 20 most-visited. America's most popular park may surprise you. It's not Yosemite, the Grand Canyon or Yellowstone.

-- Jason La and Deborah Netburn