With the National Park Service turning 100 years old, you’ll have more chances than ever to visit a national park without paying an entrance fee in 2016. How about 16 free days?

The National Park Service announced an extension of entrance fee-free days to national parks during its centennial year. In 2016, you can visit all national parks, including Yellowstone and Glacier, without paying an entrance fee for a grand total of 16 days! That includes nine consecutive days in April, for National Park Week, and four straight days in August. The first free day will be January 18 in honor of Martin Luther King Jr. Day. For a full look at the schedule, visit nps.gov/findapark/feefreeparks.