Mohamed Atta had the habit of disappearing. Friends in Germany, where he went to graduate school, say he'd sometimes drop out of sight for a month or two at a time. Family matters, he'd say.
In 1996, he disappeared for a full two years. When he returned to Hamburg, he wore the full beard and long tunic of an orthodox Muslim. He founded an Islamic student group and petitioned the university for a meeting room and funds for study materials.
No one thought much of it. Atta had always been religious, and these informal sabbaticals were common among German graduate students.
Eventually, seven years after he started, Atta won his graduate degree in urban planning. His thesis described the conflict between modernity and Islam as it played out on the streets of Aleppo, an old stone city on the desert plateau of northern Syria.
When he was awarded his degree in August 1999, he declined to shake hands with the women on his review committee. It would have offended his strict religious beliefs.
Volker Hauth, an architect and friend, accompanied the somber Atta on his researches in Aleppo. It has been five years since the two spent time together, and Hauth has trouble reconciling the man he knew with the Atta who is suspected of helping orchestrate the terrorist attacks on New York and the Pentagon. Yet Hauth says that even then there were hints of what Atta would become: an Ueberzeugungstaeter, a German word that translates as "religious criminal."
"I knew Mohamed as a guy searching for justice," Hauth said. "He felt offended by this broad wrong direction the world was taking."
A year later, Atta disappeared from Hamburg for good. Once again, no one knew where he was headed.
Atta, then 31, and a Hamburg roommate, Marwan Al-Shehhi, 21, flew into the United States within days of each other in mid-2000. They headed out across the southern United States on an unusual, extended shopping trip, looking for a place that would teach them to fly American airliners.
They made stops in Oklahoma and possibly Texas before settling on Huffman Aviation in Venice, Fla., where they arrived eager as puppies. They said they were Afghan cousins who had come to America from Germany.
Atta's old-fashioned beard was long gone. So was the robe. He and Al-Shehhi wore uniforms of modern, casual America: pressed khakis and polo shirts. When they moved into a little pink house in nearby Nokomis, they brought cookies to their rental agent.
Plotting to fly airplanes into the sides of skyscrapers filled with people seems a very long way from calculating the ideal traffic volumes and street setbacks to keep an ancient Arab souk alive. But architecture and its academic cousin, planning, embrace a wide range of disciplines in the end all aimed at one thing: Making the world suit your vision of it.
This can involve building things. It can also mean removing them.
Two Coasts
Investigators and the media have talked much since the Sept. 11 attacks about the four "terrorist cells" that launched them and the supposed logistical complexities that had to be overcome.
The known information regarding the suspected hijackers, however, doesn't offer much evidence of complexity. Their long-term preparations appear to have occurred mainly in two places, Florida and San Diego. The cells in each of these places appear to have been quite small--two, sometimes three people.
The men on each coast kept to themselves and stayed below the horizon of public scrutiny. The men suspected of killing as many as 6,900 people lived on the quiet fringes of urban America without incident, in seedy rooms where landlords asked for the rent, not references. Their only known encounter with law enforcement was a single traffic ticket for driving without a license.
In the end, the original small groups were augmented by at least a dozen more terrorists, about whom very little information has emerged. The men who swelled the total number of hijackers to 19 might have been needed for little more than muscle, to help with the physical task of taking over the aircraft.
Little is known for certain about any of the hijackers. Even now, more than two weeks after they died such very public deaths, no one can be certain even of their names.
Within 72 hours of the attacks, the FBI released a list of the 19 suspected hijackers. Six of those names appear to be aliases. There is a chance even more of them are wrong. The confusion over the names complicates efforts to learn who the hijackers were and what motivated them.
What follows is a description of what is known about their lives and, especially, their movements in the final months.
The core handful of suspects was highly mobile, traveling from the United States to Asia, Europe and Africa and back again. Almost all of what they did on these trips is unknown, although authorities report meetings with other suspected terrorists--on the beach in Barcelona, at an airport in Malaysia.
