The Atacama Desert in northern Chile is one of the most inhospitable places on Earth. It's 2,600 meters above sea level and receives almost no rainfall. Visitors, when they are not tending to dry skin and nosebleeds caused by the altitude, often compare the terrain to the barren red rocks that cover the surface of Mars.

The comparison is more than just subjective. Last week the journal Science published a paper comparing the soil in Atacama with that examined by the Viking landers sent to Mars in the 1970s. Using technology unavailable to the Viking landers, scientists have isolated organic compounds from the Atacama soil. The hope is that the soils will help researchers design better experiments for detecting life in Martian soil.

Almost lifeless though the desert is, however, a different group of scientists has another good reason to go there: the four giant white cylinders of the Paranal Observatory. These form the European Southern Observatory's imaginatively named Very Large Telescope.