The building's Web site says that as many as twelve thousand people were working on the building at the same time.

VOA: special.2010.03.31

On Earth Day, the artist and building designer Maya Lin will launch a Web site about the Earth's endangered plants and animals.

VOA: special.2010.04.21

The Council explains on its Web site that early tall buildings were generally measured from the ground floor to the top of the building, not including flagpoles.

VOA: special.2010.03.31