This is the public square above the Kölner Philharmonie, a concert hall that was opened in 1986. The design was apparently revolutionary, the hall has no columns, the sound is meant to be perfect and it has a near perfect room acoustic.
It all looks quite a nice place to stand, but there are security guards standing around it to keep people off it.
Those security guards are there to keep people off the square as anyone walking on it can cause noise disturbances for those in the concert hall. So, when performances are taking place, which seemed to be every time that I walked by, they have to pay staff to keep people away. Was this really the best way to design this?