The 1905 Hippodrome, at Sixth Avenue and 43rd Street, didn’t quite live up to its name. It was a huge theater, seating over 5000 people and with a stage big enough for battle re-enactments including actual horses for the fake cavalry, but it didn’t feature horse racing like the hippodromes of the ancient world. It was torn down in 1939, a victim of the depression and changing tastes in mass entertainment, but a lot of its neighbors, including the Algonquin and Royalton Hotels and the Bar Association, are still there today in the same buildings as 1911:
The short versions of the fall of the Hippodrome is that, by the 1920s, movies had replaced diving horses, prancing elephants, and on-stage battles for spectacle. The site sat empty for a while after demolition and was then replaced by an astonishingly boring office building, also named the Hippodrome, built in stages between 1953 and 1961, and reskinned with a new glass curtain wall in the early 2000s. (As a side note, the web site for the office building appears to have been written by someone who does not know that “hippodrome” has an actual meaning.)
The main hall of the second (1890) Madison Square Garden was bigger, but was not a proper theater and was, in fact, closer to an actual hippodrome in layout and use. This left the Hippodrome the title of the largest “theater” in the city – claimed to be the largest in the world, but who knows and how could you tell? – but with a use that didn’t quite fit its name. The plan on the Sanborn map above is that of a theater blown up to a huge size, with all the required physical accoutrements, such as an asbestos curtain separating the stage from the audience. Eventually the two uses completely split, with the third Madison Square Garden of 1925 containing a huge arena space suitable for sports and the circus, and various theaters, like the 5960-seat Radio City Music Hall of 1932, taking on theatrical spectacle.
There is one footnote to the brief life of the Hippodrome that sounds fake to me but apparently is not. James Kelly, AKA Smelly Kelly, was a professional sniffer, who worked at various jobs where someone with a sensitive nose would come in handy. He was called (apparently in the late 40s or early 50s) to investigate a terrible smell at the 42nd Street station of the Sixth Avenue subway (which opened in 1940, replacing the elevated seen in the photo above). He smelled elephants, and this was tracked down to elephant feces that had been buried in the Hippodrome’s cellar and had been recently wet by a broken water main, re-activating their pungency.