The National Park Service (NPS) invites visitors of all ages to join in the celebration of its 100th birthday. With special events across the country, and free admission to all 412 national parks from Aug. 25 to Aug. 28, the NPS is encouraging everyone to #FindYourPark/ #EncuentraTuParque for the Centennial. Sleeping Bear Dunes National Lakeshore has a full day of events from 9 a.m. to 9 p.m. on Founder’s Day, Aug. 25.