Chicago Architecture Center Tour, daytime, sunny weather, Willis Tower in the background, modern glass building, steel structure, reflective windows, stone pavement, tourists walking, guide holding a blue umbrella, audio equipment around neck, smiling face, casual wear, backpack, camera around neck, looking up at buildings, group of people listening attentively, city streets, skyscrapers, urban landscape, 3/4 composition, soft natural lighting, vibrant colors, detailed textures.