This is an amazing vintage photograph of 23rd Street as seen from around 6th Avenue looking East. In the distance, you can see the Flatiron Building towering above the neighborhood.
In the foreground, there are streetcars, horse and motor carriages, and the impeccably dressed commuters of the era, almost each of which is wearing a fancy hat.
Here is a Google Street View of how the same view looks today.
View the specimen page on the Library of Congress for more info on the photo.