a substantial portion of the Carnegie Library for three years. The Carnegie Library houses the society's research library, rotating exhibits, and offices. Ninety percent of the society's historic collections, which include artworks, documents, maps, objects, and over 100,000 photographs, are stored on-site. A permanent exhibition, Window to Washington, now traces the development of the District's built environment and serves as an introduction to the society's collections. The society also provides research workshops to students and community groups, including D.C. Public Charter Schools and universities. In 2017, the Historical Society moved to a temporary location to facilitate renovation of the Carnegie Library Building. The renovated building reopened on May 11, 2019. The Historical Society now shares space in the building with an Apple Store. Notable people Mary Stevens Beall (1854–1917), librarian and secretary of the Columbia Historical Society References External links Library buildings completed in 1902 History of Washington, D.C. Carnegie libraries in Washington, D.C. Washington, D.C. Libraries on the National Register of Historic Places in Washington, D.C. Beaux-Arts architecture in Washington, D.C. History museums in Washington, D.C. Former library buildings in the United States 1894 establishments in Washington, D.C. Mount Vernon Square