Shanghai World Financial Centre

International consortium of financial firms and Japanese investors, led by Minoru Mori

KPF

Work began in 1997, but the project's Japanese investors were so badly hit by an economic collapse that year, financing became shaky and construction had to be halted. The project initially was thought dead, but instead the tower was redesigned after 9/11 to account for increased structural security. The distinctive circular cutout at the top -- a wind-diffusing  innovation -- also was changed from a circle to a trapezoid after Chinese citizens complained that it resembled the circle on the Japanese flag.