PAGE 2.Eltanin Antenna
This one was actually solved by science eventually, but it deserves a mention just because of how long it took to get round to a successful identification of the matter. An oceanographic research ship known as the Eltanin was taken some photographs of the sea floor for scientific purposes and, this being 1964, photographic quality was not what it is now.
Finding an object down in the depths of nearly 4,000 meters, the image appeared to show the antenna of an extra-terrestrial object. For nearly four decades this item remained unidentified as it was too deep to go down and look at and it wasn’t until 2003 that it was found to be just a sea sponge.