Bureau of War Risk Insurance in NHB, by Unknown, 1918, Smithsonian Archives - History Div, Clerks of the Bureau of War Risk Insurance occupying the Natural History Building, now the National Museum of Natural History. On the request of President Wilson, the Board of Regents closed the museum to the public on July 16, 1918, making available to the government the ground and two exhibition floors (138,600 sq. ft.). The museum reopens to the public in April 1919..