In the three weeks since my family and I returned from a 26-day, 25-state, 8,100-mile trip around North America, I’ve been trying to deduce exactly what it is that makes the United States so special.

Determining that would be incredibly difficult even if we had somehow managed to see everything there is to see in our country, which of course we didn’t. Visiting half the 50 states means by definition there’s another 25 we never got to.

So what is the most impressive thing in the United States?

One possibility is located on the western bank of the Mississippi River in St. Louis, Mo. The planning and construction of the Jefferson National Expansion Memorial was truly remarkable. Conceived of in 1933 by civic leaders concerned with revitalizing their city’s crumbling waterfront, what ultimately became the Gateway Arch was designed in 1947. However, ground wasn’t broken on the planned tribute to the nation’s westward expansion until 1959, and the memorial wasn’t actually finished and dedicated until 1968. Perhaps the oddest fact about the world’s tallest stainless steel monument: It isn’t just 630 feet tall; it’s also precisely 630 feet wide.

Another remarkable and unique bit of America is located atop a 1,278-acre site 5,725 feet above sea level in western South Dakota. Gazing up at the 60-foot granite likenesses of the heads of Presidents Washington, Lincoln, Jefferson and Theodore Roosevelt carved into the side of Mount Rushmore never fails to inspire awe, no matter how many times one has visited there.

Not every extraordinary thing in the United States requires looking skyward. The 390 miles of passageways that comprise the world’s longest known cave system lie underground at 52,830-acre Mammoth Cave National Park in south-central Kentucky. Learning the history of just the two-mile stretch we toured provided further evidence that America is full of wonders, from its Rocky Mountain highs to its subterranean depths.

We were wowed by vastness of Montana, the beautiful rolling hills of West Virginia, and the wonder of the mighty Mississippi, which we observed from four different states. But what’s most important about our country isn’t any well-known natural or man-made attraction.

It’s the hostess at the Chinese restaurant in Greeley, Colo. who gave us a package of delicious almond cookies just because we had come all the way from Maine just to eat there.

It’s the woman at the gas station in Brownsville, Ky. who spent 10 minutes of her Sunday morning thanking us for visiting her town of 1,000 people and giving us several terrific reasons to come back someday (and to bring our friends!).

It’s the 65-year-old doctor from Philadelphia who took time off from a thriving practice to fly to Los Angeles, rent a Winnebago to pick up his daughter and grandchildren, and drive them halfway back across the country to see South Dakota’s Black Hills.

It’s the woman at the Kwik Trip gas station in Coon Valley, Wis. who gave us free samples of delicious chocolate chip-cherry bread while excitedly telling us that her son and grandbabies live in Limestone, Maine.

It’s the aspiring lawyer from Evanston, Wyo. who after interning for a high-powered attorney in Washington D.C., decided (along with his wife, an elementary school teacher) what they really wanted was to settle down and raise their family in Wyoming.

It’s the couple from Connecticut who took our family’s picture in front of the world’s largest ball of sisal twine in Cawker City, Kan. (Full disclosure: We took their photo in front of it, too.)

It’s the articulate, enthusiastic woman at the Dubuque, Iowa tourism bureau, who represents her adopted city (she grew up in northern New Jersey) with genuine pride and passion.

It’s the panhandler in Wentzville, Miss. who was so polite that my 11-year-old felt compelled to comment on it.

It’s the night desk manager at the hotel in Custer, S.D., an art teacher originally from California who works weekends so she can raise her son in a healthy environment.

It’s our guide at Rocky Mountain National Park, a man in his 70s who still goes to Africa each year to help build homes for the needy.

It’s the generous, hospitable families who hosted us in Schnecksville, Ft. Collins, Boulder, Berthoud, Butte, St. Paul, Westerville and Farmington Hills.

It’s the waitress at Cheyenne restaurant who drove 50 miles from Laramie so she could pick up an extra shift. Even more impressive (at least to me): She’s using the money to pay her way through the University of Wyoming, where she’s studying to become ”¦ a high school English teacher.

Mt. Rushmore, Mammoth Cave and the Gateway Arch are all truly awe-inspiring. But after nearly a month of sightseeing I’m more convinced than ever it’s the ordinary, extraordinary people who actually comprise our nation that are without a doubt its greatest asset.

— Andy Young teaches high school English in York County, which is about as far south (or west) as he plans to travel in the immediate future.