The pinyon pine clutched the rock face with a life-or-death grip that has continued for decades, its deeply furrowed trunk twisting upward in a constant quest for sunlight. While ancient-looking, the gnarled pine was just a youngster in this place – and far from alone as an impressive symbol of survival amid challenging conditions.

Looking across the ruggedcanyon, I could see a largely vertical forest of pinyons and junipers, clinging to precarious footholds across the steeply sloping walls. But what my friends and I were walking a trail to see were the 900-year-old cliff dwellings of the Sinagua people within the canyon – another impressive example of survival amid challenging conditions.

Sinagua means “without water.” These people found ways to live for more than 100 years within the Sonoran Desert 7,000 feet above sea level by developingcliff dwellingswithin the steep, marginally terraced limestone walls of Walnut Canyon,located southeast of present-day Flagstaff, AZ.

The Sinagua built stone walls across large openings underneath massive rock overhangswithin the canyon. Some rooms were situated to protect them from winter’s cold, others from summer’s heat; there were work rooms and storage places for food and water.

Drought-resistant corn, beans and squash were grown; they ate parts of the prickly pear cactus and yucca plant, and gathered pinyon nuts. In all, an estimated 20 species of wild plants within or near the canyon were used for food and medicine. Game was plentiful on the rim.

Using these God-given resources, their ingenuity and endless hard work, the Sinagua were able to cling to life in this canyon just as tenaciously as the pinyon pine. Eventually, the Sinagua moved on and probably assimilated with the Hopi Nation.

What had brought me tonorthern Arizona recently was an annual gathering of old college buddies. There was Dave, who lives in Vandergrift; Jeff, a suburban Bostonian; Jim, a suburban Philadelphian; Paul, who joined us from Lexington, KY; and our host, Tom, who has a home in Flagstaff.

We’d decided to visit Walnut Canyon National Monument and were pleasantly surprised to discover that the National Park Service had waived admission fees for the day in celebration of the Park Service’s 100th birthday.

In an interesting coincidence, upon my return home, I learned that the National Park Service is making all five of its units in southwestern Pennsylvania fee-free as of October 1, 2016. Flight 93 National Memorial near Shanksville and Friendship Hill National Historic Site near Point Marion, always have been fee-free; but now Allegheny Portage NHS near Gallitzin, Fort Necessity National Battlefield near Farmington, and Johnstown Flood NM near St. Michael also will no longer charge admission fees.

Unlike Walnut Canyon and other NPS sites nationwide that are waiving fees on an occasional basis to celebrate this special year in Park Service history, the fee-waiver at the Western Pennsylvania sites will be ongoing for the foreseeable future.

Our western Pennsylvania sites all tell stories that are every bit as dramatic and interesting as the Sinaguas’ narrative in northern Arizona. And the same is true for the 407 other sites administered by the National Park Service across the nation.

This year offers great opportunities to visit our national parks – notonly because admission fees are being waived (at least on an occasional basis)or eliminated, but because special programs are being offered at many sites as well. For more information on all of these sites, visit www.NPS.gov.

As for our Walnut Canyon experience, I think our reunion group was impressed. If I don’t sound very certain of that,it’s because – as usual – Iwas too slow for the rest of the group, who’d left me behind on the trail.

Just as I caught up, Jim said, “This was fabulous.”

To which Jeff responded, “Yes, this was cool – and short. It’s time to watch some football.”