This is part of the falls at Eau Claire Gorge, on the north side of Algonquin Park, Ontario, just past the park boundary. The falls are quite big and the gorge is steep, so you can't get too close, but the trail is a nice walk and the overlook is a nice view.
I think this is actually called the Atrium mall, but I'm not completely sure. I found this while wandering around downtown Toronto. An extreme wide angle lens helped to accentuate those diagonal lines.
