Hillwood.  Washington, DC, US.

"Marjorie Merriweather Post bought Hillwood in 1955 and soon decided her home would be a museum that would inspire and educate the public. Her northwest Washington, D.C. estate endowed the country with the most comprehensive collection of Russian imperial art outside of Russia, a distinguished 18th-century French decorative art collection, and twenty-five acres of serene landscaped gardens and natural woodlands for all to enjoy. " Source: Hillwood Official Site.