my most interesting moment of "entry" was in 1983 in Alaska, Nome. I wasn't a citizen, but had some work to do at the US Military base which tests EVERYTHING US Army buys for cold handling, from electronics to weapon systems.
I was let in after 30 seconds interview, and my Russian accents was much thicker in those days. After I asked the leutenant I was working in if they were concerned about me being from the Soviet Union, which was still in tact back in a day, he told me the truth:
every day Russian satelite flys over and they were doubting very much that I can see more than the satelite camera with .01 inch by .01 inch resolution can not
