There are a lot of signs here to tip you off, but you can guess what year this photo was taken, and what these New Yorkers were protesting? We'll update later with the answers, and more photos of the scene.
P.S. Obviously if you know the exact month or date, and/or copy the original photo's caption, you are cheating, and your answer will be deleted.
UPDATE: We've now added more photos, showing that these photos were taken in June of 1960, when beatniks took to City Hall to protest against the closing of Greenwich Village coffee houses. According to Reconstructing The Beats, earlier that month, the FDNY closed the Gaslight, a coffee shop in the neighborhood. "Coffee shop owners and beatniks, suspicious of corruption among local Tammany Hall leaders and angered by what they regarded as harassment by fire inspectors, organized protests and demonstrations. John Mitchell, the owner of the Gaslight, lead a protest march of one hundred beatniks and was arrested for disorderly conduct. The assistant fire chief said he would delay closing two more coffee houses until the following day, because he feared that 'a riot is brewing.'"