In the background is the new building, the Freedom Tower, although it isn't going to use that name, but rather One World Trade Center. It's very large, and dominates the Manhattan skyline. But as you look at it from either of the pools, it feels like the pool dwarfs the skyscraper.
You'll note that darker square area of the building is a 187' tall giant block of concrete.
The view down from the building of the memorial site must really be something to see.