Eltanin Antenna

Due to its regular antenna-like structure and upright position on the seafloor at a depth of 3,904 metres (12,808 ft), some proponents of fringe and UFO-related theories including Bruce Cathie have suggested that it might be an extraterrestrial artifact.

The 1,850-ton displacement vessel Eltanin was originally launched in 1957, and served with the United States Navy as a cargo-carrying icebreaker.

The first public mention of the unusual subject of the photograph was a news item which appeared in the New Zealand Herald on 5 December 1964, under the heading "Puzzle Picture From Sea Bed".

In 1971 the object was identified as Cladorhiza concrescens, a species of carnivorous sponge by Bruce C. Heezen and Charles D. Hollister in their book The Face of the Deep.

The book reproduces the photograph taken by the USNS Eltanin as well as a redrawn version of a drawing by Alexander Agassiz which originally appeared in his 1888 Three Cruises of the Blake.