then to the Taliban office in Quetta, Pakistan, where they were to contact a man named Umar al Masri. Atta and Jarrah left Hamburg during the last week of November 1999. Shehhi left by himself around the same time; bin al-Shibh followed two weeks later. "Umar al Masri" turned out to be a nonexistent person. The name was a code word that instructed members of the Taliban office to escort the men to Kandahar, Afghanistan, where they were convinced to join the al-Qaeda network and wage jihad against America. They met with Osama bin Laden himself and swore their loyalty to him. Mohamed Atta was chosen by Bin Laden as the leader of the group that would attack America; Atta would contact Bin Laden several more times before the attacks. The men then returned to Germany to enroll in flight training school, and later moved on to flight training schools in the United States at the recommendation of one of their instructors based in Germany. The members of the Hamburg Cell were a boon to the 9/11 plot, which Khalid Shaikh Mohammed had proposed to Bin Laden in 1996. The Hamburg students were fluent in English, educated, accustomed to the Western lifestyle, radically Islamic, and capable of learning to pilot aircraft. "Bin Laden and Mohammed Atef wasted no time in assigning the Hamburg group to the most ambitious operation yet planned by al-Qaeda," the 9/11 Commission Report says. Many al-Qaeda members lived in the Hamburg apartment at various times. In all, 29 men listed the apartment as their home address while Mohamed Atta's name was on the lease. Reportedly, Khalid Shaikh Mohammed visited the apartment repeatedly. German intelligence monitored the apartment, but did not find any evidence against the residents. Both the United States' Central Intelligence Agency and German Intelligence have received criticism for failing to share information on these and other al-Qaida members. Hamburg Cell film The film Hamburg Cell is a docudrama on the planning and execution of the attacks. A co-production between Channel 4 in the UK and CBC in Canada, it was shown in the UK during September 2004, amid criticism that this was too close to the anniversary of the attack. Using computer-generated imagery, the film's producers were able to show the twin towers of the World Trade Center, before the attack, in the background. Ziad Jarrah is featured calling his girlfriend, Aysel Sengün, from