Grand Canyon of the Yellowstone -- The vertical structures to the upper right are not human-made; they are hexagonal basalt columns -- gigantic mineral crystals, if you will -- that are often formed when magma is exposed.  I've seen similar structures elsewhere in this state (the famous Devils Tower to the east), the Devils Postpile near California's Mammoth Mountain, and the Kilt Rocks along the east coast of the Trotternish at the Isle of Skye, Scotland.  

Photo is taken with the Nikon N90, Tamron 28-200mm zoom lens, scanned ISO200 film on Kodak PhotoCD.