Mount Vernon is the most popular historic estate in America.  Located just 16 miles south of Washington, D.C., the plantation rests on the banks of the Potomac River.  Fifty acres of the estate are open to the public. Four gardens showcase heirloom plants known to have been at Mount Vernon in the late 1700s. Washington himself designed the landscape which includes 13 trees that stand today as the last living witnesses of Washington's lifetime. Expires 12/31/2013.