The amphitheatre at Epidavros, Greece. This is a composite of three photos. I first tried stitching them automatically together in Photostitch, but the structure came out banana-shaped, so I ended up doing it manually in Photoshop. As you can see, there is a "scar" from the stitching in one place, but otherwise it turned out pretty good, considering.
From my collection of photos taken on film. Taken on a school trip in 1989.