- Standing on the rim of Arizona's Grand Canyon, gazing into the vast width and depth of multi-hued rock carved over millions of years by the Colorado River
- Hiking among the world's tallest trees in California's Redwood National Park or the world's biggest trees in California's Sequoia National Park
- Riding an airboat over the surface of the Florida Everglades, checking out the crocodiles sunning themselves on the nearest land banks
- Following the boardwalks leading past steaming mud pots and geysers in Yellowstone National Park as bison wander freely in the distance
- Driving the winding Skyline Drive (speed limit: 35 mph) through Virginia's mountainous Shenandoah National Park during fall foliage season
- Climbing as far as you dare up Half Dome, Yosemite's most iconic granite formation and symbol
- Touring Mammoth Cave in Kentucky, the world's longest complex of underground caverns
- Sailing Alaska's Glacier Bay on a small ship cruise in search of whales, orcas, seals, and other sea mammals
- Marveling at the sometimes weird, always fascinating rock formations in Utah's Bryce Canyon, Arches, and Zion national parks
- Stopping for fresh popovers after hiking the rugged Maine coast on a sunny day in Acadia National Park
- Discovering the diversity of life and attractions in California's great desert parks, Death Valley and Joshua Tree
- Viewing the sunrise and then biking down Haleakala volcano on Hawaii's island of Maui – the world's longest downhill bike ride