What is it About the Atacama Desert That Makes it so Mysterious?

is it THAT similar to Mars?

Many people compare this mysterious place to the surface of Mars. Apparently one of the driest regions on earth has a mysterious, unsolved question:

In the Atacama Desert, no flowers bloom, no insects buzz, and no rain ever falls. This is the driest place on Earth. There was once water here, evidence is everywhere you look, but why has it dried up? This is the Riddle of the Atacama.

Geologists STILL are not sure what happened to all the water that was once here. What is even more fascinating, is some scientists describe the surface as being very similar to Mars in this particular region. Seriously. What do you think could have caused this environmental mystery?

Here is more on this region from wikipedia with an interesting comparison:

Comparison to Mars

In a region about 100 km (60 mi) south of Antofagasta, which averages 3,000 m (10,000 ft) in elevation, the soil has been compared to that of Mars. Owing to its otherworldly appearance, the Atacama has been used as a location for filming Mars scenes, most notably in the television series Space Odyssey: Voyage to the Planets.

In 2003, a team of researchers published a report in the journal Science in which they duplicated the tests used by the Viking 1 and Viking 2 Mars landers to detect life, and were unable to detect any signs in Atacama Desert soil in the region of Yungay.^[21] The region may be unique on Earth in this regard, and is being used by NASA to test instruments for future Mars missions. The team duplicated the Viking tests in Mars-like Earth environments and found that they missed present signs of life in soil samples from Antarctic dry valleys, the Atacama Desert of Chile and Peru, and other locales. However, in 2014, a new hyperarid site was reported, María Elena South, which was much drier than Yungay, and thus, a better Mars-like environment.