These American parks are a must-see: br Bryce Canyon (Utah): It has been voted the most beautiful national park in the country.br Death Valley National Park (California): It is the largest national park (outside Alaska) in the United States.br Great Sand Dunes National Park and Preserve (Colorado): It shelters a set of dunes, the highest in North America (229m).br Katmai National Park (Alaska): It is famous for its valley of Ten Thousand Smokes formed following the eruption of Novarupta in 1912.br Yellowstone National Park (Wyoming): It is the oldest national park in the world. It is a UNESCO World Heritage Site.br Grand Canyon (Arizona): Thanks to the extraordinary views that it offers to its visitors, it is classified as a World Heritage Site.br The Everglades (Florida): It's the 3rd largest national park in the country. It is listed as a World Heritage Site by UNESCO.br Hawai‘i Volcanoes National Park: It is home to Kīlauea, one of the world's most active volcanoes and Mauna Loa, the world's highest volcano.