At low tide there's a narrow sandy "beach" that appears under the Manhattan end of the Brooklyn Bridge. The horizontal shadow across the foreground is the Brooklyn Bridge above. While the public is not allowed access to this area I've often seen people climb the 3-ft barrier to dip their feet in the East River. At any time other than low tide this spot is completely under a few feet of water.
The bridge in the foreground is the Manhattan Bridge (looking at the Manhattan tower). Way off in the the distance (left) is the Brooklyn tower of the Williamsburg Bridge.