NPR's Melissa Block talks to Oliver and Sheila Lawn, former code-breakers in World War II who have been called in to try to decipher the meaning of mysterious letters carved into a monument at Shugborough House in Staffordshire, England. The letters -- D.O.U.O. S.V.A.V.V.M. -- are believed to be a code, and their meaning has never been established. Some have even speculated that they could be linked to the Holy Grail.
Copyright 2004 NPR
