This massive commercial building sits on the river front and, while not an especially attractive building, its size and footprint cause it to be photo worthy.  It’s positioned where the Chicago River’s main branch breaks into the north and south branches, so there are a lot of interesting spots to walk around the water and capture the building.  At night, there are light shows projected onto the building creating even better photo opportunities.  

https://www.architecture.org/learn/resources/buildings-of-chicago/building/merchandise-mart/

https://en.wikipedia.org/wiki/Merchandise_Mart