Bells tolled at ground zero and solemn tributes unfolded across the country as Americans looked back on the horror and legacy of 9/11. People gathered Monday at memorials, firehouses, city halls, campuses and elsewhere to observe the 22nd anniversary of the deadliest terror attack on U.S. soil. Nearly 3,000 people were killed when hijacked planes crashed into New York’s World Trade Center, the Pentagon and a rural Pennsylvania field. Vice President Kamala Harris is joining the ceremony at the trade center. President Joe Biden is due to join service members and their families at a ceremony on a military base in Anchorage, Alaska.