The Search For The Coronation Stone Men of the Thames River Police equipped with searchlights and grapples using an under-water periscope as they search the bottom of the Serpentine Lake in Hyde Park, following a report that some persons had bean seen to drop a heavy object into the water. A nation wide search is now being made for the historic Coronation Stone stolen from Westminster Abbey, London, during the early hours of Christmas Day. December 29, 1950. (Photo by Sport & General Press Agency, Limited).