Today marks the 100th anniversary of the creation of the United States National Park Service. From its beginnings with Yellowstone National Park, today more than 84 million acres of pristine American forests, mountains, beaches, lakes and everything in between are managed by NPS. Besides offering countless views, trails and opportunities to connect with nature, each National Park serves as a living classroom where millions of Americans learn about the nature conservation each year. The National Park Service offers a number of online resources for teachers looking to bring these lessons into the classroom. Google also launched this stunning interactive site , which allows you to virtually experience several national parks with NPS rangers as your guide. For the centennial, check out these NewsHour Extra classroom resources on national parks and the continuing efforts to preserve and protect "America's best idea." Classroom article: 5 things to know for the 100 year anniversary of the National Park Service Daily News Story: Ancient sequoia trees suffering in California drought Daily News Story: Navajo divided over plans for Grand Canyon aerial tram Daily News Story: Out of control crayfish threaten nation’s deepest lake PBS NewsHour report: Pair tackles 59 national parks in 59 weeks Compiled by Adelyn Baxter