A craft of some size flew slowly over the Great Lakes Naval base during my tenure at boot camp.

In early 1963 I was in Navy boot camp at Great Lakes Illinois.  While stand watch one night a craft of considerable size appeared over the base.  It was moving very slowly and completely silent.  It's hard to estimate size but I would guess 200 Ft. in diameter and at less than 2000 Ft. altitude.  It had rectangular "windows" on the outer circumference which glowed with a red-orange light as the craft slowly revolved.  I don't recall anything about the actual shape other than it was round. I think I was so transfixed by the lights that I never tried to make out anything else.  Or perhaps it was just such a dark night that the outline couldn't be seen.  I don't really know.  The craft moved slowly toward the far end of the base.  There were probably hundreds of trainees looking out the barrick windows.  As I stood there dumbstruck a base security truck pulled up to the gate I was guarding and ordered me to get it open and fast.  I did so even though my orders were that no one, not even the C.O.  was to be allowed to use that gate.  After my watch was over the sentry from across the highway which divided the two parts of the base and was in my company came over and asked me, with his mouth hanging open, if I had seen that.  Everyone saw it.  I never heard another word from anyone about it.
Date is approximate.  If anyone else who saw the same event, we would welcome any additional reports.  PD