I remember feeling a little guilty when other parents were surprised that my children had never been to Disney World. How could we deny our kids Space Mountain and Tomorrowland? But to Megan, 20, and Joey, 18, the "happiest place on Earth" was a national park visit each summer.

So far we have visited 10 (plus two in Canada).

The inspiration probably came from my father, who liked to load up the VW camper and head west with family in tow. I remember bears feeding out of car windows at Yellowstone (when they still dumped garbage, hard to imagine now). And a sleepless night at Old Faithful Lodge worrying about it catching fire after my dad's casual comment about how "fast it would go up."

My husband and I started our annual summer adventures in 2004 when the kids were 6 and 8. Yellowstone was our first stop. The Roosevelt cabins were a wonderful first night in the park.

The next summer it was Zion, Bryce and the North Rim of the Grand Canyon. A framed poster in Joey's bedroom shows the famous "Angel's Landing" hike at Zion. I remember trying to convince a 7-year old boy that he was not allowed to do the last part of the hike, which involved holding onto chains where one misstep meant a sheer drop to the canyon floor. And I recall loving the historic lodge at the North Rim, in Grand Canyon National Park, and our hike down the North Kaibab Trail there. One of Joey's favorite memories was lying on the ground at night at the edge of Bryce Canyon after a ranger program on light pollution. We were in one of the darkest and least light polluted places in the U.S., turning off our headlamps and looking up at the stars.

In 2006 we visited Glacier, the favorite park of both Megan and Joey. Why? The mountain goats, Going-to-the-Sun Road and the crystal blue water of Lake McDonald. And who could forget the majestic Prince of Wales Hotel in Waterton — on the Canadian side of the border — looking right out of a fairy tale on that big bluff?

After a detour to Canada for Banff in 2007, we visited Yosemite and Sequoia/Kings Canyon. We saw trees that make you speechless. Jumped off Muir Rock into the icy river at Kings Canyon. At Yosemite, we hiked to Vernal Fall, enjoyed Curry Village and beat the heat by swimming in the Merced River. The only negative is how incredibly busy this park was — we could never get truly away from all the people.

The Grand Tetons included a hike to Phelps Lake and the big jumping rock (a tip we learned from a local). I was too scared to make the 30-foot plunge, but the kids had no fear.

Washington's Olympic National Park, a 2010 visit, was so different from the others. Such variety in one park — the rain forest (and the giant banana slugs), the beach, staying at the historic Lake Crescent Lodge. We were fortunate to have a rare sunny day and a bonfire on the beach at Kalaloch Lodge.

We also visited Rocky Mountain in 2013 and had a return trip in 2015.

A constant theme through each of the parks was the water: swimming, jumping, diving into the most beautiful and cold lakes and rivers (The coldest? Probably Avalanche Lake in Glacier).

What did these visits mean to our children? For Megan, "it instilled the love of nature in me. Traveling to these places where nature is preserved made me realize the true impact humans have on this planet."

Does Joey regret not going to Disney World? "Not a chance. I am thankful that our government preserved these places."

We didn't miss a summer, until busy schedules and teenage summer jobs got in the way. Cleaning out Megan's drawers once she left for college, I came upon old "Junior Ranger" badges she had worked so hard to secure.

Last summer we had the chance to return to Glacier with Joey, and hike to Sperry Chalet. Our only regret is that Megan was not with us. But I know her love of nature is part of her character. She and her two best friends from grade school did their own Boundary Waters trip last summer after being on eight trips with her mom, aunts and cousin.

Yes, children grow up and go their own way. But I know the tradition we started as a family will get passed on to their children someday. While the glaciers in Glacier National Park will likely be gone, I hope the old wooden boat on the park's Lake Josephine will still be putting along, creating memories for another generation.

Sue Eich, a public relations executive who lives in Minneapolis, recently returned from a trip to Yosemite with her sisters; most years find them on a girls' trip to the Boundary Waters and Quetico wilderness. Her daughter and son both attend college.