Arecibo Telescope

The Arecibo Telescope is now destroyed by a collapse.
The radio telescope was a spherical reflector dish built into a natural sinkhole at the Arecibo Observatory which was completed in November 1963. 
For more than 50 years, the Arecibo Telescope was the world's largest single-aperture telescope. In July 2016 the Five-hundred-meter Aperture Spherical Telescope (FAST) in China was put into service.
On 19 November 2020, the National Science Foundation announced that they would close and dismantle the telescope. On 1 December 2020, the telescope collapsed.