(Photo by Sarah Ventre- KJZZ)

Hikers make their way up the Echo Canyon trail at Camelback Mountain.

Outdoor gear and sporting goods retailer REI is closing its stores on Black Friday for the second year in a row, encouraging its employees and customers to spend the day outdoors. National and state parks have joined the campaign and are offering free admission at some parks.

Arizona is one of the states that opted-in, offering free admission to any state park and inviting the visitors to post photos on Instagram, Twitter and Facebook at @AZStateParks.

But visitors need a park pass to participate — and those were available through Wednesday — as REI stores are closed on Friday.