Didn't see it myself as I'm up in Scotland, but my brother-in-law was visiting Chicago that week for work and he mentioned seeing something odd over the lake on Tuesday evening. He's not into any of this stuff at all, completely sceptical type, but he said it was hovering totally silent for a good few minutes before just vanishing. He didn't think to film it which is frustrating.
What time did you spot it exactly? And when you say triangular, are we talking sharp defined edges or more like a diffuse triangular glow? I've been reading a lot lately about the recurring triangle craft reports over the Great Lakes going back decades and I'm wondering if theres a pattern to the sighting times. Did anyone notice any effect on their phone or car electronics nearby?