Chicago Architecture Institute, modern building, glass facade, steel structure, angular lines, urban landscape, cityscape, Willis Tower, sunset lighting, warm glow, busy streets, pedestrians walking, trees lining the sidewalk, autumn leaves, American flag waving, stone pavement, stairs leading to entrance, large glass doors, interior lobby with escalators, minimalist decor, natural light pouring in, soft shadows, 3/4 composition, wide-angle lens.