In 1968, the Soviet ballistic missile submarine K-129 disappeared in the Pacific Ocean with its entire crew. The Soviet Union searched for the vessel but failed to locate it. American intelligence did. What followed became one of the most ambitious secret engineering operations of the Cold War. ([CIA][1])
The CIA created Project Azorian, building the enormous Hughes Glomar Explorer under the cover story of deep sea mining. Its real mission was to descend more than three miles into the Pacific and secretly lift part of a Soviet missile submarine from the ocean floor while Soviet vessels were nearby. ([CIA][1])
The operation is now documented, but important details about what intelligence was recovered remain classified. What exactly did the United States bring back from K-129?