Temperatures are quickly cooling down, and you might be inclined to take advantage of the last few long, sunny days with a weekend visit to the great outdoors. This Saturday, September 26, you can bask in the open air of any national park for free, as part of National Public Lands Day.

According to the National Park Service, the holiday has been held on the fourth Saturday of every September since 1994, and it’s also the nation’s largest single-day volunteer effort. It’s up to you whether you’d like to partake in the service side or simply go for a stroll. Opportunities for volunteering include tree-planting, park cleanups, and more; you can find events near you here. There are also a number of virtual events you can tune into, which range from wildlife livestreams and virtual tours to how-to webinars (a Virginia State Parks ranger, for example, will teach you how to make a bee hotel).

There are more than 400 areas run by the National Park Service across the U.S., and many of them aren’t parks in the traditional sense of the word; the Statue of Liberty, Alcatraz Island, and countless other monuments and historical sites are also run by the NPS. Wondering if there might be one closer than you thought? Explore parks in your area on this interactive map.

If you do decide to celebrate National Public Lands Day on public lands, you should contact the park—or check its website—before you head there so you know of any coronavirus-related protocols they've put in place. And for those of you who can’t take advantage of the free admission on September 26, the National Park Service will also waive all entrance fees for Veterans Day on November 11.