You can't miss I.M. Pei's pyramid entrance to the louvre museum. I think it works architecturally simply because it is so out of place with it's surroundings. To have made any structure sympathetic with the surrounding wings of the museum would have resulted in something truly horrendous. The Pyramid works, in my view, but note that it's often not the fastest way into the louvre and on a sunny summer's day the heat outside in the courtyard can be stifling and the authorities take exception to people playing in the surrounding fountain pools.
This is a photo taken inside the louvre Pyramid, looking up towards its apex. The concrete structure houses the elevator.
