The National Portrait Gallery, along with the Smithsonian American Art Museum, occupies the historic Patent Office Building, re-opened in 2006. One of the finest neoclassical structures in the world, its Greek Revival design dates from 1836. Completed in 1867 as the third Federal building in Washington, DC, this national landmark was hailed by Walt Whitman as 'the noblest of Washington buildings'. Several important early American architects were involved in the original design of the building. Here inventors such as Alexander Graham Bell and Thomas Edison obtained title to their work. During the Civil War, it served initially as temporary barracks, hospital and morgue, and, in 1865, as the site of Abraham Lincoln's second inaugural ball. In 1958, the Smithsonian acquired the building, saving it from demolition.