WTC

My inference is that the 450,000 gallons of water that fill the WTC pools, is the space that was where the buildings sat. The reason that the pools are so deep is possibly because of how deep the WTC sat in the ground. In the text they stated that the "two reflecting pools stand in the footprints of the former WTC buildings". That statement had me think that the pools are part of the originial foundation of the WTC.