The Shugborough Inscription is a sequence of letters - O U O S V A V V, between the letters D M - carved on the 18th-century Shepherd's Monument in the grounds of Shugborough Hall in Staffordshire, England, below a mirror image of Nicolas Poussin's painting, the Shepherds of Arcadia. It has never been satisfactorily explained, and has been called one of the world's top uncracked ciphertexts.