Omni Shoreham Hotel

From www.culturaltourismdc.org:

Designed by Joseph Abel, over its six decades the Shoreham has attracted its share of Washington, DC's wealthy, famous, and powerful, including Gary Cooper, Marilyn Monroe, and even President Harry Truman, who held his weekly poker game in one of its rooms. For many years, the hotel was a favorite of the United States Senate.

The lobby looks out onto a section of Rock Creek Park. Also, there are bars and restaurants scattered throughout the huge complex, including the Marquee Cabaret.