Atacama Desert, Chile
The Atacama, which stretches 600 miles (1,000 kilometers) from Peru's southern border into northern Chile, is what climatologists describe as an absolute desert. It is filled with sterile, bone-dry stretches where rain has never been recorded for as long as humans have been measuring the weather. As a result, much of this parched area is totally devoid of vegetation [source: Vesilind].
With features such as sand dunes and lava flows, it's not hard to imagine the Atacama as being similar to the landscape that robotic probes — and someday, astronauts — would find on Mars. That's one reason that NASA has used the Chilean desert as a test site. In 2005, for example, a NASA probe detected microbial life in the Atacama's seemingly barren soil, as scientists are hopeful that they'll also be able to do on Mars [source: NASA].