Horseshoe Bend Slot Canyon: What do you get when you have orange and red sandstone and millions of years of flash flooding? Probably one of the most beautiful places you'll ever see in your life - I'm not joking. In other words, you have no excuses - go check it out! There's barely any hiking involved, and they can all be seen in just a few hours.
One can't travel through Arizona and NOT see these amazing natural wonders.