What used to be there?/!.
Living, for the moment, in New York City, I am surrounded by constant change. The block I live on looks different than it did when I moved in. The block I work on even more so. It fascinates me to return to a neighborhood I last haunted only 2 or 3 years ago, and find it completely changed.
Some of the changes in my work neighborhood, Murray Hill in Manhattan, have already been nicely documented by the CUNY project “The Digital Murray Hill”, at murrayhill.gc.cuny.edu. Take, for instance, the southeast corner of the intersection of 34th Street and Park Avenue.

“The 71st Regiment Armory; Built: 1892-1894, Architect: John R. Thomas ; Rebuilt: 1904, Architects: Clinton and Russell; Razed: 1970's. The original Romanesque Revival building burned down in 1902 and was replaced in 1904 by a red brick structure in the style of a medieval castle.

“Caption reads: Armory of the Seventy-First Regiment, N. G. N. Y., Park Avenue, New York, N.Y. ; Clinton & Russell, Architects. The 71st Regiment Armory; Built: 1892-1894, Architect: John R. Russell; Rebuilt: 1904, Architects: Clinton and Russell; Razed: 1970's. The original Romanesque Revival building burned down in 1902 and was replaced in 1904 by a red brick structure in the style of a medieval castle. The 250 foot tower was modeled after the Palazzo Pubblico of Siena, Italy.”

3 Park Avenue, 111 East 33rd Street; Built: 1977; Architects: Shreve, Lamb & Harmon. The Norman Thomas High School occupies the first 11 floors. The school's address is on 33rd Street . The remaining 31 stories are used as offices. This site was previously home to the 71st Regiment Armory.
Those who know me well, or at least know me recently, know I have a bit of an architecture fetish. And they know that pretty much all “modern” styles of architecture appeal to me very little. Leaky, cheap boxes, all straight lines and practical impracticality, pfffffah. And the international style particularly bores me to tears. That said, I don’t mind the current inhabitant of the “3 Park Avenue” address, as the exterior takes on a pleasant, dusky hue in the early morning light, and in the spring the moon sits above it just so around 7am, giving it an otherworldly quality.
And besides, can you imagine attending a high school that takes up 11 stories of a skyscraper? I have to say, considering the size of the school, the students of Norman Thomas have been nothing but well behaved. Not a peep from the youth, all day long. It saddens me that the school could be closing in the near future. It occupies, after all, some extremely valuable Manhattan real estate. You wouldn’t think so walking past it, however, as the sizable third commercial space on the street level has been vacant for over a year now. The Starbucks remains, but the Hallmark store folded months before the current recession hit its stride.

Oops, I’m slipping. ALL HAIL BLOOMBERG! King of kings. Look at his works, ye mighty, and despair. Etc, etc. That should cover it.
Funnily enough, the previous tenants of 3 Park Avenue seemingly could not be more opposite the philosophy of Norman Thomas.

The sentiment of reluctance to accept the Irish and German immigrants didn’t come just from a

Too many men, not enough jobs, wages sinking as desperate and hungry immigrants were willing to work for a pittance and live in squalor (and robber barons more than happy to oblige them)—these things are as American as apple pie. But ah! There’s politics again.
In 1919, the Veterans Association of the 71st Regiment published a short book on its history,

“’Up to 1840 the American workman was as independent, manly, and well situated a citizen as there was at that time in any land; he had work in plenty and he did it well, and never dreamed of ‘striking,’ for he and his employer were friends and neighbors. He lived comfortably, but without ostentation, ‘feared god and spoke the truth,’ was a patriotic citizen and a useful, manly man. But during that decade of 1840-1850, his good fortune came to an end; hordes of foreign immigrants, fleeing from the distress and famine of their native country, came to the land of promise; and the consequent lowering of wages, causing strong competition for situations, as well as the entry of the ‘foreign element’ into politics, filled the native American with alarm and indignation; as well might they have swept back the ocean from our shores with a broom, as to turn from New York the flood of immigration, or prevent the worthy foreigner from obtaining wealth and office.’ But they made an attempt, and organized the ‘Order of the United Americans.’ It was at a convention of this order, held in the Broadway Tabernacle, 340 Broadway, in the fall of 1849, that William B. Ferguson, who became a member of Company C, and subsequently of the Veteran Association until his death, offered a resolution that a committee be appointed for the purposed of raising a regiment of militia, to be composed of native Americans only.” (History of the 71st Regiment, NGNY: American Guard-“Pro Aris et Pro Focis”, page 1).
I could get into the various ironies of that quote, but I think they’re self evident.

And with that an independent, non-government political interest group set about starting it’s own militia, in service, of course, of the “true” American people. In October of 1850, the “American Rifles,” as they were first known, set up shop. In 1853, they became the “American Guard,” trading their long rifles for muskets. By 1857, they had switched to smaller rifles.
The 71st was officially homeless until about 1868, when it moved into its first Armory on 32nd street, according to the 1919 history. The regiment took up residence in the armory at 34th and Park in 1894, escorted, according to the New York Times, by "it's old time friend, the Seventh Regiment."
The 71st infantry participated in many national and international conflicts, particularly during

The 71st was more or less disbanded in 1993, by which time it was a mostly African American regiment of the National Guard. It had moved down to 125 West 14th St, and the second, towered Amory was demolished in the 1970s to make way for a tower of office space.
So that's what used to be there.

Photo by Walter How.