Marks have been carved on walls and ceilings at Creswell Crags, between Nottinghamshire and Derbyshire.

It was previously though to have been graffiti from the time before the caves were shut off.

But it could be something more sinister– these marks are designed to turn away evil spirits.

The marks, however, appear to have been added to over time.Experts say this may indicate a need to strengthen the protection against underworld spirits.

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