LEGO Architecture: Marina City
This is a close-up of the Marina City model. The LEGO architect (Adam Reed Tucker) purposefully left some sections open apparently to allow the viewer to see the internal construction methods.
Photo of LEGO Architecture exhibit by Wally Bahny for TechRepublic
I believe the open areas are actually parking. Odd, but there's parking spaces with cars in them all around the outside of the building. Not sure how they get up there, I always assumed some sort of elevator.