The Loop’s blue building on LaSalle Street

All that remains of the circa-1910 Otis Building at 10 S LaSalle is four stories of its original façade, and it’s all you may have ever noticed of the 37-story tower that replaced it.

I’d passed the building many times without ever looking up to see the 1986-vintage skyscraper behind the classic terra cotta and granite façade. Reviewing our aerial photographs, however, the bright blue cobalt tower is an eye-popping presence with green striping on its corners, staggered setbacks, and a zipper of projecting bay windows above a 2-story recessed bay.

According to Emporis, 10 South LaSalle is the tallest building in Chicago designed by Canadian architects.

You can see more of YoChicago’s aerial photographs at Flickr.