Incredibly, the city authorities even admit it was operating as a radical recruitment center for terrorists in the intervening decade.

The New York Times:

The authorities in Hamburg said Monday that they had shut down the mosque there where several of the hijackers involved in the Sept. 11 attacks had met because it remained a source of radicalization nearly a decade later.

The Masjid Taiba mosque, known at the time of the hijackings in 2001 as Al Quds mosque, was "closed effective immediately," according to a statement by the Hamburg Interior Ministry.

The mosque's closing came after a group of radicalized young people associated with the mosque, most of whom were German citizens with roots in Muslim countries, traveled last year to the border region between Afghanistan and Pakistan.

Police searched the mosque and the apartments of leading members starting at 6 a.m., and seized the group's assets. Photographs published on the Web site of the daily newspaper Hamburger Abendblatt showed police carrying computers out of the mosque in Hamburg's St. Georg neighborhood.

This is not unusual in Germany. If you read John Rosenthal's work on the German government's extraordinary laxity in policing radical islamists in their own country, you know that they bend over backwards to accommodate terrorists in their midst. The fact  that it has taken them nearly a decade to shut down a mosque that radicalized the 9/11 plotters makes sense in that context.

How many more terrorists were created because of the stupidity of the Germans? Let's hope we never find out.