Exploring abandoned homes and buildings can be one of the creepiest things that you ever do with your time. There is just something about a building that was once full of life, now reduced to dark nothingness, that draws people in. That feeling only amplifies if you happen to be exploring a place with a creepy history, say an abandoned psychiatric hospital, for example.
Once inside one of these places, you might see and hear things that aren't there or couldn't possibly be real. Usually there is no evidence of these things after they happen, but every once in a while we get some disturbingly convincing footage. Take, for example, the mysterious blue light spotted inside an abandoned hospital in the video below.
So was it a ghost or what? Sadly, probably not. The more likely answer is it's the flashlight or lantern of other urban explorers in the building or someone squatting on the property. Still, though, there is always that hope (however slim) that it's something otherworldly.