It had an indoor theater (which held 1000) and a roof top theater that allowed for summer performances (since air conditioning was not available at the time). The "Roof Garden" encompassed the roof of it's theater and the Republic Theatre next door (also built by Hammerstein but was leased out.)
Houdini may have been one of the last big named acts to play Hammerstein's Victoria because in 1915 the theater was torn down because the competition from the new Palace Theatre down the street was too much.
Houdini at Hammerstein's
Hammerstein's plays an important roll in the career of Houdini. In 1912, Houdini was the headliner on the bill. Also on that same bill from Jan 29-Feb 3 was comedian and satirist Will Rogers. A few months later in July, 1912 Houdini was back and to promote his appearance he presented an outdoor escape. Reports say he was tied to the tower of the Heidelberg Building in Times Square. The Heidelberg Building stood at 1459 Broadway and was renamed the Crossroads Building and eventually torn down in 1984. Today, the Times Square Tower stands at that location.
During that same month, Houdini was using his overboard packing case escape from the East River to promote his appearances at Hammerstein's Victoria. He was also able to do the feat in the theater because a previous act had a large tank of water and Houdini used it to recreate his underwater packing escape.
In 1914 Houdini debuted is Walking Through a Brick Wall Illusion at Hammerstein's which was written up in the Variety Newspaper on July 18, 1914.