UAP near DT Chicago along Lake Michigan

I was at my Parents 18th floor Condo (Lake Point Towers) overlooking Lake Michigan & Navy Pier, when their dog started barking frantically in the next room.  As this was quite unusual to hear, I ran in to see what the fuss was about.
There I observed in the very large floor to ceiling picture window, a flat, spiral, circular, one dimensional, electric-like 60hz humming, very brilliant white circular light @ 10meters in diameter and only 5 meters away from my window vantage point.  The ‘flat disc’ descended slowly and closely along the high rise floors of the building and I watched it travel to about 30 feet above the ground and shifted path to fly over Lake Michigan where I lost sight as it went beyond my sight of view.
I immediately ran downstairs to confirm its location, but object was nowhere in sight and the doorman told me he did not see this object.
Although many years have passed, this UAP experience was life changing and the memory stays with me to this day.
Note: I was reminded of my sighting from your recent post of: Occurred : 9/21/2019 23:13 (Entered as : 9/21/2019 23:13) Reported: 9/30/2019 11:10:28 AM 11:10 Posted: 10/4/2019 Location: Gallipolis, OH Shape: Circle Duration:8 seconds