To celebrate their 100th anniversary as well as honor National Park Week, the National Park Service is letting everyone in for free for the next two weekends!

All 118 national parks—including local favorites Muir Woods, Pinnacles, and even Yosemite—will be free on April 15-16 and 22-23. The fee waiver includes entrance, commercial tour and transportation entrance fees. Other fees, such as those for reservations, camping, tours, and concessions, are not included.

Well, what are you waiting for? Get outside.