Almost 70 years later, Lord Norman Foster commissioned a new tower at the site. It was the first LEED “Gold” skyscraper in New York, and the first skyscraper to be built after 9/11. Designed using a “diagrid,” a triangular based exterior truss, the building claims to use 20 percent less steel than a conventionally framed steel building. Additional environmental features in the building include a system of embedded plastic tubes in the floor slabs to provide cooling and heating by circulating water, and a large water feature in the main lobby atrium to cool and humidify the air.