Marilyn Art Mosaic in Deep Zoom
In most browsers, you should be able to see a mosaic below although you might need to download Microsoft's "Silverlight" add-in, which is a tiny and safe download, and well worth the effort.
If you click on the picture it'll zoom closer; spin the mouse wheel and it'll retreat...
David Bowie
Notice the pin-board arrangement of the photos here - this is a unique capability.
Brighton Pier
An abstract image of the iconic and crumbling West Pier, made from real family snaps.