Arches National Park & Canyonlands National Park, UT Professional Review and Guide
"Arches National Park, just 5 miles north of Moab, features the world’s largest concentration of natural red and golden sandstone arches. This is a sight your children will long remember. More than 2,000 majestic arches plus red-rock canyons, fins, spires, and balancing rocks give this landscape an extraterrestrial aura.
Canyonlands National Park is quite close, and certainly worth a visit, although it’s more rugged and not as accessible for families, particularly those with young children. (In fact, it’s the state’s least visited national park, albeit the largest.)"