The Arecibo reply was the name given to a crop circle that appeared in farmland next to the Chilbolton radio telescope; home to the Search for Extraterrestrial Intelligence Institute (SETI) in Hampshire, UK, on 19 August 2001. It was 75 feet wide and 120 feet long. The design is so named because it appears to be a response to the Arecibo message, which SETI transmitted into space in 1974.
Own work based on: Arecibo reply message.png
Johannes Rössel