Officials today tested one of the reflecting pools at the National September 11 Memorial, turning on the water that cascades into the pool.
The two pools reflect the original location of the twin towers.
In August, crews began planting 16 swamp white oaks at the World Trade Center site. They were the first of nearly 400 trees to be planted around the eight-acre memorial to the nearly 2,800 people were killed when terrorists attacked the twin towers on Sept. 11, 2001.
The trees will dot a cobblestone plaza surrounding two huge pools built on the footprints of the destroyed towers.
The memorial is expected to open in September 2011.