Observing in the world's driest desert

ALMA is a revolutionary astronomical telescope, comprising an array of 66 giant 12-metre and 7-metre diameter antennas observing millimetre and submillimetre wavelengths. The array is situated on the breathtaking Chajnantor Plateau in the Chilean Andes, at an altitude of around 5000 metres. Chajnantor is the highest major observatory site in the world, and the atmosphere above the plateau is the driest in the world, with the exception of Antarctica.