One World Trade Center: A Bombproof Base and the 1,776-Foot Spire Ruling

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After the September 11, 2001 attacks killed 2,996 people and destroyed the twin towers, whose framed tube design had freed up open office floors, the Lower Manhattan Development Corporation ran a master plan competition in 2002. Daniel Libeskind's asymmetrical design won in February 2003, but David Childs of Skidmore, Owings & Merrill took over the tower and pushed for a symmetrical, tapering form. Leaseholder Larry Silverstein feared tenants would avoid high floors, and late in 2003 the architects announced a compromise. In 2005 the NYPD's concerns about truck bombs led to a 185-foot windowless concrete base and a setback of 65 feet from West Street, up from 25 feet for the original towers.

Planned prismatic glass panels for the base cracked in testing and were dropped in 2011 for angled glass fins with LED lighting. The cornerstone was laid July 4, 2004, real construction waited until 2006, and the $3.9 billion cost made it the world's most expensive building at the time. Silverstein's argument that the attacks were two insurance occurrences ended in a mixed verdict capping payouts at $4.577 billion for the complex. The Port Authority dropped the Freedom Tower name in 2009, Condé Nast became the anchor tenant, and in 2013 the Council on Tall Buildings and Urban Habitat ruled the 408-foot mast a spire, setting the height at 1,776 feet.

• The roof sits at 1,368 feet, matching the original North Tower.
• Removing the mast's fiberglass radome saved $20 million but made it look like an antenna.
• Fuel cells using phosphoric acid generate 4.8 megawatts on site, and the tower earned LEED Gold.
• The 65-foot lobby holds a 90-foot mural by José Parlá.
• New York Times critic Michael Kimmelman called the tower "opaque, shellacked, monomaniacal."