"Exhibits interpret the role of plants in supporting earth's diverse and fragile ecosystems and in enriching human life. Public displays are located in the Conservatory, on the surrounding terrace gardens, and in adjacent Bartholdi Park. Established by Congress in 1820, the U.S. Botanic Garden is one of the oldest botanic gardens in North America. The garden's first greenhouse was constructed in 1842; since 1849 the Garden has been located at the eastern end of the Mall. The Garden has been administered through the Office of the Architect of the Capitol since 1934."