Architectural artifacts of St Louis, Gateway Arch, iconic monument, stainless steel, shiny surface, reflected sunlight, afternoon lighting, cityscape background, urban atmosphere, Missouri River, Jefferson National Expansion Memorial, historic significance, neoclassical style, ornate details, grand staircase, marble flooring, intricate moldings, monumental columns, vibrant American flags, warm natural light, cinematic composition, 3/4 view, subtle texture.