Germany's connection to the September 11, 2001 attacks

"This day has changed the world," German President Johannes Rau said. He had watched in shock as the burning Twin Towers of the World Trade Center collapsed in New York.

Nearly 3,000 people were killed on September 11, 2001, when Islamist terrorists hijacked four passenger planes and turned them into deadly weapons.

Germany’s head of state struggled to find the right words: "We do not know what political or social consequences what happened today will have — what we have watched unfold on our television screens in shock, barely able to comprehend or even reflect on it."

It soon emerged that the victims include people from 92 countries, among them 11 Germans.

The following day, a rapidly spreading rumor was confirmed: Three of the four suspected hijackers had recently lived in Hamburg. The Islamist terrorists were thought to have been led by Egyptian-born Mohammed Atta, who had come to the northern German city in the early 1990s to study.

At some point, the young man became radicalized, particularly at Hamburg's Al-Quds Mosque, which was later closed by German security authorities. He spent the final three years of his life in an apartment shared with two other suspected attackers in the Harburg district.

The so-called Hamburg terrorist cell was believed to have included six men, among them Moroccan national Mounir al-Motassadeq. He was charged as an accomplice in the world's first trial related to the September 11, 2001, attacks . In 2003, the Hanseatic Higher Regional Court sentenced him to the maximum 15-year prison term for aiding and abetting thousands of murders and for membership in a terrorist organization.

After serving his sentence, al-Motassadeq was deported to his native Morocco. Another suspected attacker from the circle around pilot Mohammed Atta was Ramzi Binalshibh, who was born in Yemen and had been held without trial at the US detention facility at Guantanamo Bay since 2006.