This is a flooded area of tunnels and chambers; ground water and runoff from storm drains up top have long ago changed this small cave to a deep, still lake, with a couple large, submerged tunnels cut into the rock. There is very little current, and quite often the water is nearly perfectly still, enough to catch a glimpse of stars above when the world Above has a cloudless night, the light pollution diffused enough to discern the major constellations of the northern sky.

Children are known to swim here, supervised by an adult or one of the older teenagers assigned to the task. The youngest ones tend to wear vests, hollow tubes of patched rubber that have been inflated with air so that the little ones can float. The water will lazily flow on its way farther below, towards the Chamber of the Falls. There are quite a few barriers between this pool and that cavern, enough that a child who caught a particularly strong current and was pulled away can be rescued without much fuss.

A flat path, carved out of a solid rock archway, connects one side of this cave to the other.