[Zhukov]

I went on a ghost tour in Edinburgh once, it was fun. There was a "ghost" that people had reported seeing walking down the corridors of the old sewer systems, and we were of course looking for said ghost. I saw it walking past down the end of a very long hallway, and pointed it out.

People went nuts, and a woman screamed. You could see a dark shadow moving left and right.

When we went down the hallway it turned out it was just a brick wall, part of which was discoloured. The dark discolouration being seen from a dimly lit distance caused it to appear as if it was moving. Even after a rational explanation of the "ghost" was seen with people's own eyes, and explained by the tour guide as being so, some people still wouldn't budge over the fact that they had seen a ghost.