Construction on the ELT sliding doors

This photo shows an enormous beam structure for the sliding doors of ESO's Extremely Large Telescope (ELT) in the Atacama Desert, Chile. During the day, these doors will protect the telescope mirrors from the dusty desert environment, but at night, they will slide open to unleash the world's biggest eye on the sky. In the background, the main structure of the ELT itself can be seen perched on Cerro Armazones.