In 1998 I travelled to San Francisco and shot this truly dreadful photo of Alcatraz. If you can't make it out through the haze and scratches, Alcatraz is the dark, flattened blob at lower left. I don't think even Photoshop could improve this misfire terribly much.
I scanned the original colour negative with my CanoScan, which normally produces excellent results. But you can't make an Ansel Adams out of a...an Earl J. Woods, I guess.