You know, of course, that the film directly inspired an actual theft soon after, from the American Museum of Natural History in New York?
http://en.wikipedia.org/wiki/Jack_Roland_Murphy

...although that wikipedia article doesn't mention Topkapi: I was first told the story of Murph the Surf by a copy editor at AMNH who said that Murph studied the film and based his plan for the heist off it - according to wikipedia he needn't have bothered. Anyway, getaway seems to have been his main problem.