Devastated by the 1906 earthquake and fire, San Francisco’s City Hall was rebuilt to prepare for the 1915 Panama-Pacific International Exposition. A commission comprising John Howard, Frederick Meyer, and John Reid, Jr., established a Beaux-Arts central plaza with long, axial views surrounded by classical buildings, including a city hall, state building, public library, opera house, theater, and exposition hall. The exposition hall and plaza were constructed by 1915, while the other buildings were added over the next two decades. The city’s cultural and administrative center, the plaza has been redesigned several times as public needs have been reassessed, with involvement from several well-known landscape architects. In 1936 Thomas Church created the War Memorial Court, situated between the theater and opera house. From 1956 to 1958, Brooks Exhibition Hall and the adjacent parking structure were designed by Wurster, Bernardi & Emmons in collaboration with Skidmore, Owings & Merrill. The team included landscape architect Douglas Baylis, who also redesigned the plaza in the Modernist style, creating a planting plan with rows of pollarded London plane and olive trees, the latter removed in 1998. In 1975 Lawrence Halprin, along with the architectural firms Mario Ciampi and Associates and John Carl Warnecke & Associates, created the United Nations Plaza on the site’s eastern edge. Set within the middle of the plaza, the Helen Diller Playgrounds opened in 2018 and were designed by Andrea Cochran Landscape Architecture in partnership with The Trust for Public Land. The Civic Center was listed in the National Register of Historic Places in 1978 and was designated a National Historic Landmark in 1987.