The office tower at 4 World Trade Center has opened in lower Manhattan.
A ribbon-cutting was held Wednesday for the 978-foot building.
It's designed by prize-winning architect Fumihiko Maki.
The building faces the Sept. 11 memorial's south reflecting pool.
The Port Authority of New York and New Jersey expects to move into 4 World Trade in 2015.
The authority lost its home in the twin towers during the 2001 terror attacks.
The official opening means it can start building out its new office space.
The site's marquee skyscraper, One World Trade, is expected to officially open sometime in 2014.
Another office tower, at 7 World Trade Center, opened in 2006.