(Photo: AP) A private developer little known to the general public, Silverstein signed a 99-year lease for the twin towers just six weeks before the attack. His lease with the Port Authority of New York and New Jersey remains in place, making Silverstein, 72, a key figure in the rebuilding of the site. After much behind-closed-doors wrangling over the site's final design, Silverstein and redevelopment officials reached an agreement that leaves in place architect Daniel Libeskind's centerpiece (the 1,776-foot Freedom Tower) but hands the lead role in construction to Silverstein's hand-picked architect, David Childs.