Almost every roll-down gate in the city is accompanied by at least a couple of these sticker advertisements put up by gate repair companies hoping they'll get the proprietor's business next time the gate malfunctions. The stickers generally go unseen by the public (I never noticed one until your webmaster pointed them out to me), but they are EVERYWHERE. For example: this, this, and this.
This supremely weird-looking apartment building was once a Steinway piano factory, a predecessor to the current piano-making complex.
Beneath the viaduct leading to the Hell Gate Bridge
Set between the Hell Gate and Triborough Bridges, this beautiful swimming hole was one of eleven WPA-built city pools opened in the summer of 1936 (here's a great history of public swimming in the city). They were all enormous, but this one was the king. Designed for about 3000 swimmers, with facilities that could accommodate up to 6200, it even hosted the US Olympic swimming and diving trials in 1936 and 1964. You'll normally find more people frolicking here on a hot summer day; at this time of the evening, the pool is open only for lap swimming.
Adjacent to the swimming pool, this one hasn't stood the test of time so well. It has been unused for decades, but there are plans in the works to turn it into an amphitheater, with the triple-level diving board integrated into the stage.