The official name of the U.S Pentagon rebuilding following the damage the building sustained on September 11th, 2001. The name "Phoenix Project" is derived from the mythological bird of rebirth and immortality.

On October 18, 2001, slightly over a month after the 9/11 attacks, full scale demolition began of the entire damaged area. The goal was also set to reoccupy everything affected at the point of impact by September 11, 2002.

On November 19, 2001, four weeks ahead of schedule, demolition was completed. The reconstruction phase of the project began that same exact day.

February 25, 2002, the first slab of new limestone was placed on the face of the Pentagon. By April 5th, 2002 the structural concrete work was completed and by June 11th, 2002 the last of approximately 4,000 pieces of new limestone was placed on the face of the Pentagon.

On August 15th, 2002, tenants from the affected part of the Pentagon moved back in, and sure enough, by September 11th, 2002, the area affected by the initial point of impact was reoccupied and operational. A total of 3,000 Pentagon tenants returned to work. Although the true date in which the U.S Pentagon went back to being fully operational is when the entire west side of the building was February 14th, 2003 (Valentine's Day) was reoccupied.

All in all, the project rebuilt 400,000 square feet of office space damaged on 9/11, removed 50,000 tons of debris, involved 3,000 people and cost 526 million dollars.