Construction scenes
While weather is a common culprit for photos turning out not quite as expected, it is far from the only one. Unexpected construction can do just as much damage to a beautiful photo as anything, especially if you have traveled to a different country just to see a special monument. This traveler was unlucky to encounter just such a situation when visiting Big Ben.
I suppose it is common knowledge that all structures need semi-regular maintenance, but it must feel like terrible luck to unwittingly time your vacation perfectly to coincide with said construction. At least this sightseer still got a photo with the giant clock, even though the reality was likely not what she expected!