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.