On Aug. 15, 1977, astronomers using Ohio State University's Big Ear radio telescope detected the famous "Wow! " signal, which remains unexplained to this day.
Source: [Space.com](https://www.space.com/space-exploration/search-for-life/on-this-day-in-space-aug-15-1977-mysterious-wow-signal-boosts-search-for-e-t)