NEW YORK (AP) -- The World Trade Center site fell silent four times -- twice each to mark jetliner crashes and the collapse of its iconic towers -- and solemn remembrances were held around the nation Monday to mark the fifth anniversary of the Sept. 11 attacks.

Ground zero in lower Manhattan went quiet at 8:46 a.m. and 9:03 a.m., for the impacts of American Airlines Flight 11 and United Flight 175, and again at 9:59 a.m. and 30 minutes later, when the south and north towers fell.

Family members of the 2,749 people lost in the trade center attacks held photos of their loved ones, crossed themselves and sobbed quietly as spouses and partners of the victims read their names, one by one.

"We've come back to remember the valor of those we've lost, those who innocently went to work that day and the brave souls who went in after them," former Mayor Rudolph Giuliani said.

(Copyright 2006 by The Associated Press. All Rights Reserved.)