This arsenal at 64th Street was already outmoded as a military facility when the Civil War broke out in 1861. Built by Martin Euclid Thompson, it had been an auxiliary headquarters for the Seventh "Silk Stocking" Regiment since 1848. Although it was vacated by them in 1857 when the city claimed the building for its new Central Park, the arsenal continued as a military storage center in the early years of the war. It subsequently became a museum (precursor to the American Museum of Natural History), a weather bureau, and an art gallery. It also served as a makeshift zoo until 1870, when the Central Park Menagerie was given more permanent grounds behind the Arsenal. Today it serves as the headquarters for the Parks Department.