The Arecibo Telescope was an amazing tool for astronomers. Built in the early 1960s, it had a 1,000-foot-wide dish and was capable of both receiving and transmitting radio signals. It did radar mapping of near-Earth asteroids, Venus, and the moon, discovered water at the polar regions of Mercury, searched for alien civilizations, and even send a radio message from Earth to a globular cluster 25,000 light years away. So when it collapsed in 2020, many astronomers wondered if it could be rebuilt.
Source:
phys.org