Brooklyn Bridge Park's new pop-up swimming pool not only offers families a free and fun way to cool off but also one of the best views in the city—plus the option of morning kids' swimming lessons during the week ($125 per week-long session). Slated to remain in the park for five years, the swimming hole is 30 by 50 feet and 3.5 feet deep and holds a maximum of 60 people, so keeping an eye on the littlest swimmers will be easy. After a dip, families can dry off on one of the 25 lounge chairs dotting the artificial sand beach while marveling at their proximity to the Brooklyn Bridge.