Thursday 3rd November 2011. All interviewees at the CTBUH 2011 Awards Symposium were asked the same question: "What do you think is the single biggest limiting factor that would prevent humanity creating a mile-high tower or higher?" Responses include: Werner Sobek, Werner Sobek Engineers; John Bowers, Gehry Partners; Chris Wilkinson, Wilkinson Eyre Architects; Matthias Sauerbruch, Sauerbruch Hutton; Adrian Smith, Adrian Smith + Gordon Gill Architecture; Craig Gibbons, Arup; Craig Webb, Gehry Partners; Dr. Akira Wada, Architectural Institute of Japan; Toby Blunt, Foster + Partners; Joseph Rechichi, Forest City Ratner Companies. Less