9/11 attacks reverberate as US marks 21st anniversary, people pay tribute

Americans remembered 9/11 on Sunday with readings of victims' names, volunteer work and other tributes 21 years after the deadliest terror attack on US soil.

A tolling bell and a moment of silence began the commemoration at ground zero in New York, where the World Trade Center's twin towers were destroyed by the hijacked-plane attacks of Sept. 11, 2001.

Firefighter Jimmy Riches' namesake nephew wasn't born yet when his uncle died, but the boy took the podium to pay tribute to him.

You're always in my heart. And I know you are watching over me, he said after reading a portion of the nearly 3,000 victims' names.

Victims' relatives and dignitaries also convened at the two other attack sites, the Pentagon and a field in Pennsylvania.

Other communities around the country are marking the day with candlelight vigils, interfaith services and other commemorations. Some Americans are joining in volunteer projects on a day that is federally recognized as both Patriot Day and a National Day o