A huge radio telescope in Puerto Rico has collapsed after decades of astronomical discoveries.
The US National Science Foundation (NSF) said the telescope's 900-ton instrument platform fell onto a reflector dish some 450ft (137m) below.
It came just weeks after officials announced that the telescope would be dismantled amid safety fears, following damage to its support system.
The Arecibo Observatory telescope was one of the largest in the world.
It was a key scientific resource for radio astronomers for 57 years, and was also made famous as the backdrop for a scene in the James Bond film GoldenEye and other Hollywood films.
The NSF said there had been no reports of injuries following the collapse.
What happened to the telescope?
The telescope consisted of a 1,000ft-wide radio dish with a 900-ton instrument platform hanging 450ft above. The platform was suspended by cables connected to three towers.
Two cables had broken since August, damaging the structure and forcing officials to close the observatory.
A review last month found that the telescope was at risk of catastrophic collapse and said the huge structure could not be repaired without posing a potentially deadly risk to construction workers.
Officials said the structure would be dismantled.
Following the announcement, three members of Congress, including Puerto Rico's representative Jenniffer González, requested funds "to enable the NSF to continue exploring options to safely stabilise the structure".
Jonathan Friedman, who worked for 26 years as a senior research associate at the observatory and still lives near it, told the Associated Press news agency of the moment the telescope collapsed on Tuesday.
"It sounded like a rumble. I knew exactly what it was," he said. "I was screaming. Personally, I was out of control... I don't have words to express it. It's a very deep, terrible feeling."
The NSF said it was "saddened" by the collapse and would be "looking for ways to assist the scientific community and maintain our strong relationship with the people of Puerto Rico".
