The term "Glomar Response" in law - meaning a "neither confirm nor deny" response to Freedom of Information Act requests - comes from a ship called the Hughes Glomar Explorer, which was ostensibly owned by mysterious and eccentric billionaire Howard Hughes, but was actually a CIA project.
In 1972, Hughes was approached by the CIA to help covertly recover the sunken Soviet submarine K-129. The Soviet sub, allegedly containing nuclear missiles, had sunk near Hawaii four years earlier. Thus a special-purpose salvage vessel for "Project Azorian" (aka "Project Jennifer") was born, and Hughes' involvement provided the CIA with the plausible cover story of being a research vessel searching for undersea manganese nodules.
Wikipedia on the K-129:
After having successfully completed two 70-day ballistic-missile combat patrols in 1967, K-129 was tasked with her third patrol to commence 24 February 1968 with an expected completion date of 5 May 1968. Upon departure 24 February, K-129 reached deep water, conducted its test dive, returned to the surface to report by radio that all was well, and proceeded on patrol. No further communication was ever received from K-129, despite normal radio check-ins expected when the submarine crossed the 180th meridian, and when it arrived at its patrol area.
By mid-March, Soviet naval authorities at Kamchatka became concerned that K-129 had missed two consecutive radio check-ins. First, K-129 was instructed by normal fleet broadcast to break radio silence and contact headquarters; later and more urgent communications all went unanswered. By the third week of March, Soviet naval headquarters declared K-129 "missing", and organized a massive air, surface and sub-surface search and rescue effort into the North Pacific from Kamchatka and Vladivostok.
This highly unusual Soviet surge deployment into the Pacific was correctly analyzed by U.S. intelligence as probably in reaction to a submarine loss. U.S. SOSUS Naval Facilities in the North Pacific were alerted and requested to review recent acoustic records to identify any possible associated signal. Several SOSUS arrays recorded a possibly related event on March 8, 1968, and upon examination produced sufficient triangulation by lines-of-bearing to provide the U.S. Navy with a locus for the probable wreck site. One source characterized the acoustic signal as "an isolated, single sound of an explosion or implosion, 'a good-sized bang'."
Soviet search efforts, lacking the equivalent of the U.S. SOSUS system, proved unable to locate K-129, and eventually Soviet naval activity in the North Pacific returned to normal. K-129 was subsequently declared lost with all hands.
As the story goes, eager to recover the sub and gain Soviet military secrets, the CIA took the Glomar to the spot and attempted to dredge it up from the ocean floor. The official story says that only a third of the sub was retrieved, as its hull broke up during the effort. Other sources claim the entire sub was brought back intact, and that the "it broke" version was yet another cover story within a cover story, to further conceal our Government's possession of classified Soviet materials if the project were to be found out.
And in 1975, that's just what happened. The New York Times planned an expose on the Glomar, but held the story back when the Nixon administration privately urged them to do so, on the rationale that it could cause a dangerous international incident if the truth were known. The Los Angeles Times also got wind of the story, ignored Nixon's requests, and ran the story anyway. After the cat was out of the bag, the New York Times went ahead with their article also.
When journalists attempted to get more info via the Freedom of Information Act, the CIA refused to either confirm or deny the existence of such documents. This type of evasive reply has since come to be known as the "Glomar Response" or "Glomarization."
But does the coverup stop there?
For every odd event related to the CIA, espionage, and secrecy, there's always someone on the internet who wants to bring extraterrestrials into it. The Glomar case is no different, but there is some food for thought in the idea that the real purpose of Project Azorian was to recover an alien craft that crash-landed in the ocean.
If you're willing to wade waist-deep in that swamp, start here and here and also here. And check out Bob Lazar's site when it comes back online, which is supposed to be any second now. Lazar, famous for his claims of insider knowledge of Area 51, is regarded variously as a genius or a charlatan. As is the usually the case, the truth likely falls somewhere in between.
Lazar is quoted as having said that the aliens arrived in the vessel from the fourth planet of the second star of the binary stellar system Zeta Reticuli. He also claimed to have seen a total of nine different types of alien spacecraft, and viewed autopsies of alien corpses. Recovered crafts such as that allegedly obtained by the Glomar were supposedly taken to Area 51 to be studied and reverse-engineered. Others have claimed that some of that reverse engineering is done by Raytheon at Kentucky's Blue Grass Army Depot.