Vermilion Cliffs National Monument in Arizona features an array of sandstone rock formations, towering hoodoos and surreal slot canyons. The monument, established in 2000, was named after the vibrant red hues that dominate the landscape. Once you get a permit to visit this exclusive outdoor excursion, make sure to visit the 'Wave.' It's a stunning geological wonder, with flowing layers of rocks that appear frozen like red liquid. Other visual treats include Cobra Arch and the White Pocket formation of sandstone structures, featuring swirling patterns, crossbedding and a combination of colours, including white, red and orange.