8 Ways to Celebrate the 100th Anniversary of the National Park Service

April 16-24 is National Park Week, when admission fees will be waived at all park sites that have them. (For more free admission days in 2016, visit nps.gov.)

Now in theaters, National Parks Adventure is a new IMAX 3D documentary narrated by Robert Redford that explores America's most majestic terrains in all of their eye-popping glory. Find a theater near you at nationalparksadventure.com.

Airstream and Pendleton have joined forces to design 100 limited-edition travel trailers in honor of the National Park System's 100th anniversary. The trailers start at $114,600 and for each one sold from now until December 2018, Airstream will donate $1,000 to the National Park Foundation, which will be used to support preservation at Grand Canyon and Glacier National Parks. Not in your budget? Opt for a dog coat or a hat from Pendleton's National Park Collection (also celebrating 100 years!).

Guarantee that our national parks will thrive for another 100 years (and beyond!) by volunteering to clear trails, provide visitor information, plant seedlings and more. Registered volunteers who contribute 201.6 hours of service between January 1, 2016 and December 31, 2016 earn a Centennial Volunteer Challenge Coin. Want to learn more? Find opportunities near you.

Head to findyourpark.com for more information about National Park Service centennial events near you.