Four large antennas

Four large antennas for ALMA thrust to the sky at the Operations Support Facility (OSF), 2900 m above sea level. ALMA is the largest ground-based astronomy project in existence, and will be comprised of a giant array of fifty 12-m submillimeter quality antennas, with baselines of up to 16 kilometers.© Iztok Bončina/ALMA (ESO/NAOJ/NRAO)