The New York Stock Exchange Building is the headquarters of the New York Stock Exchange (NYSE). It is composed of two connected structures in Lower Manhattan, New York City. One part, the original structure at 18 Broad Street, was designed in the Classical Revival style by George B. Post; the other is a 23-story office annex at 11 Wall Street, designed by Trowbridge & Livingston in a similar style. The NYSE had occupied the site on Broad Street since 1865 but had to expand its previous building several times, and so the structure at 18 Broad Street was erected between 1901 and 1903. Within two decades, the new building had become overcrowded, and the annex at 11 Wall Street was added between 1920 and 1922. The original structure's colonnade is an icon of the NYSE; behind it is the main trading floor, a 72-foot-tall (22 m) rectangular space. The building was designated a National Historic Landmark in 1978 and a city landmark by the New York City Landmarks Preservation Commission in 1985. (Full article...)