NEW YORK (AP) - Americans are commemorating the Sept. 11 terror attacks with somber tributes, volunteer projects and a new monument to victims.
Thousands of victims' relatives, survivors, rescuers and others are expected at Tuesday's ceremony at the World Trade Center.
President Donald Trump and first lady Melania Trump plan to join an observance at the 9/11 memorial near Shanksville, Pennsylvania. A new tower honoring victims was dedicated there Saturday.
Vice President Mike Pence is attending a ceremony at the Pentagon.
Nearly 3,000 people died when hijacked planes slammed into the trade center, the Pentagon and a field near Shanksville on Sept. 11, 2001.
Since the last anniversary, a truck attack on a nearby bike that killed eight people. Months later, there was a botched pipe bombing in a subway passageway near Times Square..