City Hall: Constructed from 1803 to 1812, New York`s City Hall is one of the oldest continuously used City Halls in the nation, and houses the offices of the Mayor and City Council, the executive and legislative branches of government. Considered one of the finest architectural achievements of its period, City Hall was designed by architects Joseph François Mangin (before 1794-1818), a French émigré, and John McComb, Jr (1763-1853), a native New Yorker. The building is in the Federal style, with clear French influences that can be seen in the large arched windows, delicate ornamental swags, and more decorative Corinthian- and Ionic-style columns and pilasters. City Hall is a designated Hew York City landmark, and its soaring rotunda, dramatically encircled by a keystone-cantilevered staircase, is a designated interior landmark.
In 2010, the City launched the City Hall Rehabilitation to correct structural issues and preserve the historic building. In addition to structural repairs, the project included the installation of a new fire safety system, an energy-efficient heating and cooling system, a fuel cell, and vastly improved electrical service in order to bring the building up to 21st century standards.