There was this tricky mirror scene in Contact
The effect is: the camera is moving backwards, always facing a character running towards something and keeping the same distance from that character (who does turns, goes upstairs, etc) and always facing it, during the whole shot. When the character's hand reaches (near the camera) what appears to be a cabinet door, and opens it, the cabinet's mirror moves on the side and the image we had moves with it, as if everything (or at least the last part of the run toward the cabinet) was filmed in the cabinet's mirror (with the camera facing the cabinet, not the character).
How was this scene really made?
Is it really a mirror shot or something else?