Extra-large autonomous submarines may revolutionize intelligence gathering and espionage under the sea. One of these ground breaking projects is the U.S. Navy's Boeing Orca extra-large uncrewed underwater vehicle (XLUUV). It is much larger than any other underwater drone currently in the water. But there is a historical precursor that, despite its epic Cold War story, is not widely known. And its mission, to lay covert sensor networks in the arctic, may be as relevant today as it was then.