Students at the University of Tromso in Norway created an interactive display wall using 28 separate projectors, which in turn created a 7168×3072 (or 22 megapixel) display. The user could interact with the display by simply placing his hands in front of it.
To demonstrate the capabilities of the system one could zoom into a 13.3 gigapixel photograph as seen in this video…
You can read up more about the system at https://www.cs.uit.no/~daniels/gigapix/