The saguaro stood like sentries as far as I could see, pointing their arms in all directions.

Dumbstruck by their beauty, I paused long enough to snap multiple photos — click, click, click, click, click — before heading into the visitor center at Saguaro National Park, outside Tucson, Ariz.

I was there with a purpose beyond admiring the tall cactus with the confusing name (pronounced suh-WAHR-oh), though it was easy to get distracted. (There are 1.8 million of the giants in the park.) I was there to tap into one of the perks of — how shall we say this gracefully? — mature age: the senior lifetime pass.

Well, you don't have to feel like a senior to qualify for a pass, in this case, a jaw-dropping deal for travelers, with a very short window left in its offering.

Through Aug. 27, seniors can purchase for a mere $10 a lifetime of access to national parks across the country. Ten dollars. Really. It's been like this since 1994. Why did I not know this before? (Perhaps because when you're not 62, the discount doesn't hit your radar.)

But on Aug. 28, the price goes up-up-up to $80 for a lifetime pass, not out-of-line for a rest-of-your-life kind of purchase that provides access to more than 2,000 federal recreation sites. But that amount might give a senior pause before writing a check. An annual pass option for seniors then will be available for $20; the younger crowd pays $80.

To get the sweet senior deal, you need to show up in person at one of the federal sites and show proof of your age and residence. A driver's license will do. That's it. Well, that and $10 (cash or check only).

Minnesota has 28 such federal sites, though only one of the two in the Twin Cities still has passes available, so call ahead. The Minnesota Valley National Wildlife Refuge office (3815 E. American Blvd., Bloomington, 952-854-5900, open 9 a.m.- 5 p.m. Tue.-Sun.) reports that they expect to have sufficient supply. For a complete list of locations to purchase the senior passes in all states, see tinyurl.com/ybmo4tod.

You can also buy the pass online or by mail, but there is, of course, additional cost (another $10, for a total of $20); see details for an online application at store.usgs.gov/senior-pass and by mail at tinyurl.com/y9pedc5h.

Eligibility is strictly for U.S. citizens or permanent residents age 62 or over. Only the designated senior can buy it.

The lifetime passes cover the passholder plus three adults (children under 16 are also free). Questions? Call 1-888-275-8747, option 3, or see recreation.gov.

Hurry. The saguaro are waiting.