Arecibo Observatory

Arecibo Observatory was a major research facility in Puerto Rico that housed one of the world's largest radio telescopes built into a natural sinkhole. The site included educational centers and exhibits that explained radio astronomy and space science to visitors.

The facility was constructed in 1963 as part of a U.S. defense program and held the title of world's largest single-dish radio telescope for many decades. The telescope collapsed in 2020, bringing an end to its era of active research operations.

The observatory educated thousands of students in astronomy and engineering, establishing itself as a central institution for scientific advancement in Puerto Rico.

After the 2020 collapse, visitors can explore the visitor center and learn about radio astronomy through displays and presentations about the site's scientific contributions. The center provides a good introduction to how radio telescopes work and their role in space exploration.

In 1974 this facility transmitted the first intentional radio message aimed at extraterrestrial life, making it a landmark moment in humanity's search for contact beyond Earth. This groundbreaking transmission helped establish the site as a symbol of our cosmic aspirations.

Location: Arecibo

Address: 86VW+MWP, PR-625, Arecibo, 00612

Website: http://naic.edu

GPS coordinates: 18.34667,-66.75267

Latest update: December 14, 2025 13:04