An English professor has launched a nationwide ghost debunking exercise, which has attracted thousands of participants thus far.
Hundreds of snapshots of alleged ghosts have been posted online on a site created by Professor Richard Wiseman, who teaches Psychology at the University of Hertfordshire, for an experiment at the Edinburgh Science Festival.
The photos will be examined to see whether the ghostly figures can be explained or not, and visitors to the site have been invited to vote on whether they think the ghost is "genuine" or "fake" or "uncertain".
As per Wiseman, 42, the site had 60,000 hits on the first day and 40,000 the following day, and a national debate between sceptics and believers has taken off.
"I'm surprised that it's really taken off," the Telegraph quoted him as saying.
"I've already had 250 pictures sent to me and I've posted the best 30 online.
"Ten per cent of the population have had a ghostly experience, but no-one yet has carried out a survey of what kind of experiences they have.
"We know ghosts tend to be seen as solid figures, which only reveal themselves as ghosts when they do something like walking through a wall.
"I have had some fairly good ghost photo where it's not immediately obvious what's going on.
"Often you might see what looks like a face in semidarkness but it's just a trick of the light. The human brain is hard-wired to see faces, for instance in clouds. That's because faces are the most important things we can see around us.
"I'm pretty sceptical, and usually there's a rational explanation, but it could be that someone out there is sitting on something really interesting.
"Some of the pictures are genuinely quite creepy and they are the ones that have started to go viral," he added.
The results of the study will be announced during the Edinburgh International Science Festival, and a survey of people's ghostly experiences will also be launched next month.