May Day at the Polo Grounds

My sister-in-law recently sent me an image of her grandfather, Lazar Weiner, conducting a chorus at a ballpark. She asked me if I could track down when and where the photo was taken. Here's the picture:



The "where" was simple. The facade of the ballpark makes it clear that it is the Polo Grounds. It was the "when" that was a challenge.

The critical clue was some information we knew about Weiner: that he conducted the ILGWU chorus and was the national director of the Workmen's Circle chorus for many decades. Given this information, the banners on the facade at the park took on special meaning. Here's a detail showing the banners:



These were hung especially for the event that was being hosted at the park, as they were certainly not a regular feature at the Polo Grounds. Note that the banner at far right promotes the ILGWU, the very union whose chorus was headed by Weiner.

Everything pointed to some sort of union-related event being held at the Polo Grounds. After some brief searching, I came across an article in the New York Times from May 2, 1936, that read in part:

A group of labor unions and the Old Guard of the Socialist party celebrated May Day yesterday with a rally and open-air festival at the Polo Grounds that attracted a crowd estimated by the police at 45,000.

From noon to almost 6 o'clock there was a program featuring athletic games, pageants, a chorus of 500 mixed voices, concert and radio singers and addresses by labor leaders.

This seemed to be a perfect match for the event in the photo. But I still felt I needed something more to corroborate this, so I browsed through the same edition of the paper and came across a photo of the event at the park:



Though the photograph is taken from a slightly different angle, it is clear that the speaker system seen in both images match perfectly. Here are details from both photos that show the match:



So the image of Lazar Weiner and his chorus was taken on May 1, 1936, during a May Day rally at the Polo Grounds.