What fatelul event transpired on Mount Vernon?

Mount Vernon, located near Alexandria, Virginia, was the plantation home of the first President of the United States, George Washington. It is estimated that during his two terms as President of the United States (1789-1797) Washington spent 434 days in residence at Mount Vernon. The remains of George and Martha Washington, as well as other family members, are entombed on the grounds. In 1831 graverobbers attempted (but failed) to rob the graves.