When you think of deserts, the first thing that probably comes to mind for many is scorching heat, utter desolation and images of parched travelers crawling over a huge sand dune toward an imaginary oasis. Yet modern amenities such as sturdy four-wheel-drive vehicles, GPS units and air conditioning have turned even the most inhospitable deserts of yesteryear into potential vacation spots. Desert adventure tours have grown in popularity in recent years, offering travelers relatively inexpensive access to unique hiking, trekking, camping and wildlife-viewing opportunities. Of course, photography buffs and astronomers in search of dark skies can find plenty to be excited about as well. Here are five breathtaking deserts offering cool adventure tours.