Watch Koolhaas; Hadid; Rogers Stirk Harbour; and Foster pitch their proposals for the new L&L Tower

The series of videos below offers a fascinating insight into how this generation of "starchitects" behaves under pressure, as they each pitch to win one of the most high-profile competitions in recent years: a new tower for L&L Holding Company on Park Avenue in New York. The site has such daunting neighbours as Mies van der Rohe's Seagram building, and it will be the first full-block office tower to be built on the street in almost half a century. — guardian.co.uk