The Tower of the Empire State Building (1931) viewed through the Civil War memorial Arch (1892) in Grand Army Plaza(1867) from the Brooklyn Mirador (1970) in Brooklyn's Prospect Park. This three point alignment of the Tower, the Keystone of the Arch, and the Mirador (a lamppost on the median of the principal roadway leading into Prospect Park) bisect the arch a 90-degree angle.