Iranian President Ahmadinejad speaks at Columbia

Iranian President Mahmoud Ahmadinejad speaks at Columbia, protesters argue, huge crowd shows up to hear the Iranian President

Photos by AP Photographers David Karp, Spenser Platt & Shannon Stapleton

New York - Iranian President Mahmoud Ahmadinejad questioned the official version of the Sept. 11 attacks and defended the right to cast doubt on the Holocaust in a tense appearance Monday at Columbia University