modern architecture, Barcelona Pavilion, Mies van der Rohe, minimalist structure, reflective pools, glass walls, travertine floors, open-plan, geometric shapes, steel columns, natural light, shadow play, indoor-outdoor flow, serene atmosphere, clear sky, midday sun, architectural photography, wide-angle lens, 3/4 view, crisp details, high dynamic range, marble walls, water reflection, tranquil environment, iconic building, cultural landmark, Spain, contemporary design, sleek materials, elegant simplicity.