Atacama Large Millimeter Array

The Atacama Large Millimeter/sub-millimeter Array (ALMA) is an array of radio telescopes in the Atacama Desert of northern Chile. A high and dry site is very important for millimeter wavelength work. ALMA is being built on the Chajnantor plateau at 5000 metres altitude. It will have 66 12-meter and 7-meter diameter radio telescopes observing at millimeter and sub-millimeter wavelengths. ALMA is expected to help scientists understand how stars were created during the early universe. It will also provide detailed imaging of local star and planet formation. 
ALMA is being built by Europe, the United States, Canada, East Asia and the Republic of Chile. Costing more than a billion US dollars, it is the worlds's most expensive ground-based telescope. ALMA began scientific observations in the second half of 2011 and the first images were released to the press on 3 October 2011. The project is should be fully operational by March 2013.