In 1942 an unidentified flying object was detected on radar screens approaching the west coast towards Los Angeles – and then appearing right on top of Long Beach, where it set off a panicked anti-aircraft artillery barrage. Five years later metallic debris from a supposed crashed flying saucer were found in a field in New Mexico. Investigations of both concluded that it was highly likely no aliens were involved in either, but the incidents – especially Roswell – became part of the cultural zeitgeist. This mania was nothing new; it was just a continuation of fascination with aliens that began at the turn of century.

On this day, December 17, in 1900, half a century before news of the Roswell finding, the French Academy of Science offered a prize of 100,000 francs to the first person to make contact with an alien civilization.

Giovanni Virginio Schiaparelli, an esteemed astronomer and the director of the Milan Observatory, a man who never expressed any fervent beliefs about aliens nonetheless was the one to (unintentionally) start the mania. Schiaparelli observed Mars during its closest approach to the Earth, noticing for the first time straight lines across its surface. He called them canalli, which in Spanish denotes a natural phenomenon. But the English-speaking world dispensed with that translation in favor of an engineered channel. If canals existed on Mars, certainly intelligent martians built them.