The City Hall Post Office and Courthouse was a building designed by the architect Alfred B. Mullett for a triangular site in New York City along Broadway in Civic Center, lower Manhattan, across City Hall Park from New York City Hall. The Second Empire style building, built between 1869 and 1880, was not well received. Commonly called "Mullett's Monstrosity", it was demolished in 1939 and the site was used to extend City Hall Park to the south