you probably know Arthur C. Clarke's saying that “sufficiently advanced technology is indistinguishable from magic”. that was my exact impression when couple of days ago i've read how Soviet's SOKS was used to track USA submarines. SOKS is a device dating back to 1969 (!!) that allows to tack submarines by finding trail that they leave underwater by:
i do not know what blew my mind more in this story:
wonder what they are using and working on now, half a century later.