There are metal pylons on the Red Line mezzanine at Gallery Place, next to the escalators to the exits and to the Green and Yellow Line, that support loudspeakers. These pylons hinder the flow of passengers through the mezzanine and should be moved somewhere else.
These pylons were also used as wayfinding signs as some point, but that's been painted over, so now they're just speakers and can be easily moved elsewhere. The attached photo doesn't show the pylons clearly, but they're behind the pillars supporting the overhead signs. I don't believe they're attached to those pillars in any way.