Revellers celebrate the winter solstice at Stonehenge on Salisbury Plain in southern England December 22, 2015. Stonehenge is a celebrated venue of festivities during the winter solstice - the shortest day of the year in the northern hemisphere - and it attracts thousands of revellers, spiritualists and tourists. Druids, a pagan religious order dating back to Celtic Britain, believe Stonehenge was a centre of spiritualism more than 2,000 years ago. REUTERS/Kieran Doherty