Welcome to the ghost experiment.

Professor Richard Wiseman in association with Channel 4 Science is investigating the alleged haunting of a disused underground street in Edinburgh known as Mary King's Close - and we need your help.

There are some photographs of different parts of the underground labyrinth. You will be asked to look at one or more of the pictures and see if you can sense what type of 'ghostly' activity has been reported in each location.

We need as many people to participate as possible, so it doesn't matter whether you believe in ghosts or are a complete sceptic - please take part.