US marks anniversary of 9/11 terrorist attacks

Americans are remembering 9/11 with moments of silence, readings of victims' names, volunteer work and other tributes 21 years after the deadliest terror attack on U.S. soil. 

US marks anniversary of 9/11 terrorist attacks
Americans are remembering 9/11 with moments of silence, readings of victims' names, volunteer work and other tributes 21 years after the deadliest terror attack on U.S. soil.