This lovely building in Chicago is all about the reflections. Located where the river branches, and Wacker drive takes a turn too, the building exemplifies "contextualism", the architectural style which Chicago pioneered. So the building's facade isn't just a giant curved sheet of glass reflecting its riverside neighbours as you approach it down the river, it is also green, to reflect the Chicago river's green. But see it during a bright day, and it looks more blue. Here, at sunset, it has become the deep green of the river, reflecting it even without directly "reflecting" it.