9. Edinburgh Castle, Scotland

The iconic heritage castle is known to sit on the grounds dating back to the Iron Age. In addition to being a popular tourist destination by day, the castle is the home to a spectral dog, a headless drummer, and a phantom piper. During a 10-day scientific survey of the castle in 2001, several volunteers and scientists reported ghost sightings. Ever since, people have started taking the Edinburgh Castle seriously as one of the haunted places in the world.