USS Thresher was the lead submarine of her class of nuclear-powered attack boats in the 1960s. Named after the thresher shark, the US Navy submarine had state-of-the-art features that made it the fastest and quietest U-boat of its day, significantly pushing the boundaries of Cold War technology.But in April of 1963, the USS Thresher atomic submarine left port to perform a series of test dives off Cape Cod, Massachusetts, and never came back.When the submarine sank to the bottom of the ocean after a series of bewildering underwater phone calls, the naval community was baffled.But the Navy classified the report, only releasing scant details about the accident that took 129 lives.The mystery then lived on for several decades until a brave lawsuit brought the document to the forefront. To this day, we still keep learning about what happened on that fateful morning…