Arecibo

Arecibo was the location of an astronomical observatory in Puerto Rico in the 20th and 21st century. (TV: The Ambassadors of Death, AUDIO: Earthfall)

On 16 November 1974, the Arecibo radio telescope broadcast a message containing basic information about the human race to the globular star cluster Messier 13. Messier 13 received the message in 251,974. (PROSE: Time Traveller's Diary)

In the 21st century, it was used by UNIT to track Nestene energy units. (AUDIO: Earthfall)