Construction to build the National September 11 Memorial & Museum began in March 2006 with preliminary work to cover the original box beam columns that outline the perimeters of the twin towers. In August 2006, heavy construction work began to build the footings that will hold up the memorial, museum, and museum plaza. Work on the footings is expected to be completed in the third quarter of 2007. Steel fabrication began in summer 2007, and the first pieces of steel are expected to be erected at the WTC site in December 2007, with this work continuing through 2008. The memorial is scheduled to open on September 11, 2011. The museum is scheduled to follow, opening in 2012.

August 15, 2004 Schematic design began
January 2005 Fountain mock-up built in Toronto, Canada
September 2, 2005 Design development completed
March 2006 Foundation work and structural framework began
Fall 2006 Swamp white oak and liquid amber oak purchased and tagged
August 8, 2007 Steel beams for memorial arrive in U.S. from Luxembourg
Fall 2007 Memorial and memorial museum foundations completed
December 2007 First steel for memorial to arrive at WTC site
Fall 2008 Memorial and memorial museum superstructure to be completed
Summer 2009 Plaza paving
Summer 2010 Tree planting
Fall 2011 Memorial plaza opens
2012 Memorial museum opens