Museum Centre Pompidou in Paris

You're standing at the Centre Pompidou, which Parisians simply call Beaubourg, after the neighbourhood it stands in. Take a good look at the façade. Everything a normal building hides is hanging on the outside here: pipes, ducts, stairs and escalators. The architects Renzo Piano and Richard Rogers, both still in their thirties at the time, turned the building inside out. They were convinced they had no chance of winning, so they went all in. Their design beat 681 other entries.