Many people visit Nevada's
Valley of Fire State Park, partly owing to the proximity to Las Vegas and Lake Mead, but also because of the fantastic, multicolored landscape - the park has sizeable outcrops of pink, red and yellow rocks, eroded into striking formations, including narrow canyons, arches and pinnacles, making this one of the best (small-scale) photographic locations in the Southwest. There are few official trails, but cross-country hiking is relatively easy.
Valley of Fire - full description