Taking a smoke break at work and saw a metallic, triangular craft with three white lights at each point of the triangle (one lead light), and a blinking red light in the center. I noticed it because it was the only thing in the sky at the moment. I assumed it was an airplane at first, since I see airplanes out here all the time. But as I watched it, the shape that the white lights outlined appeared more and more to be a solid triangle. Also, I don't believe I have seen airplanes travel this particular north-to-south path almost directly over the building. (I've seen west-to-east and east-to-west far south of the building's location, and southwest-to-north-east a bit north of the building's location, but never north-to-south almost directly over the building.) The craft made no sound that I could hear, and the usual city sounds were almost non-existent. (It was around 5:15 am.) The craft traveled from north to south, slowly, in a straight line. I watched it for maybe 15 seconds, until it's path took it beyond the treeline/building line. As I watched it, I was initially convinced I was watching a regular airliner flying a little lower than usual, but as I watched it, the light pastern reminded me of a UFO sighting or two I had heard. My cell phone isn't a smart-phone, so I didn't take pictures or video. I didn't feel any excitement or fear or anything until after the craft disappeared beyond my line of sight. Then, as I considered that I might have been watching an actual unidentified flying object, I felt a little excited. I am not 100% certain what I saw was a commercial airplane, but I am reporting this just in case.