Bryce Canyon is not a canyon. No river carved it. Its amphitheaters were cut by frost, water seeping into limestone joints, freezing on roughly 170 nights a year, prying the rock apart grain by grain. The result is the densest concentration of hoodoos on Earth. A Las Vegas Grand Canyon Bryce Zion Tour reaches that rim after a climb of some 2,400 metres from the Mojave floor, and the vegetation changes four times along the way: creosote, then juniper, then ponderosa, then fir. Zion works in the opposite direction. The Virgin River still cuts downward through Navajo Sandstone, a petrified dune field over 600 metres thick, laid down when this corner of Utah was a desert the size of the modern Sahara. Southern Paiute people knew the Bryce rim as Angka-ku-wass-a-wits, red-painted faces. Mormon settlers arrived in the 1860s. Congress protected Zion in 1919 and Bryce Canyon in 1928. Both parks sit on the Grand Staircase, a sequence of cliff bands stepping north from the Colorado River, each rung older than the one above it. That geological ladder is why the two parks are read together. Utah national parks tours built around the pairing move through 200 million years of deposition in under 130 kilometres of highway. Las Vegas Grand Canyon Bryce Zion Tour tours add a third register when they take in Grand Canyon West, Antelope Canyon or Horseshoe Bend, all of it Colorado Plateau country, older still and cut deeper. Zion now receives close to five million visitors a year. Bryce, topping out at 2,778 metres at Rainbow Point, receives fewer than half that and holds some of the darkest measured skies in the contiguous United States. The air is thin and dry. Sound carries. The hoodoos erode by roughly a millimetre each year. The built environment is modest and deliberate. The Zion-Mount Carmel Tunnel, blasted 1.7 kilometres through sandstone and opened in 1930, carries galleries cut into its outer wall so drivers could glimpse Pine Creek below. Civilian Conservation Corps crews laid the switchbacks toward Angels Landing and the rim paths above Bryce Amphitheater in the same decade, using local stone so the masonry vanishes into the cliff. Checkerboard Mesa, cross-bedded and frost-scored, sits beside the highway with no interpretive fanfare. Any Las Vegas Grand Canyon Bryce Zion Tour tour eventually descends again to the desert floor, where the plateau ends and the Mojave resumes.