The Wow!_signal in 1977 has perplexed several people and the Bloop sound in 1997 has puzzled many people as well.
https://en.wikipedia.org/wiki/Wow!_signal#Celestial_location , https://www.youtube.com/watch?v=TPHh0vC7KcU
https://astronomy.com/news/2020/09/the-wow-signal-an-alien-missed-connection
https://earthsky.org/space/source-of-wow-signal-in-1977-sunlike-star-2mass-19281982-2640123
https://futurism.com/the-40-year-old-mystery-of-the-wow-signal-was-just-solved
https://phys.org/news/2017-06-wow-mystery-space.html
Strange how both occurrences were two decades apart from each other.
https://en.wikipedia.org/wiki/Bloop#Animal_origin
The Bloop Heard Beneath The Sea
https://www.youtube.com/watch?v=3BWO3D8x3AQ
The Unsolved Mystery of the Bloop
https://www.youtube.com/watch?v=JtEfHnbMWIg
https://www.theatlantic.com/video/index/543105/the-bloop-loudest-sound-ever-recorded-cara-cusumano/