A flag unfurling ceremony at the Pentagon commemorates 25 years since the Sept. 11, 2001, terror attacks as Americans across the country pause to remember and reflect. ▻ ↧ 9/11 25th anniversary live updates: Families to gather for ceremoni... Friday marks 25 years since the Sept. 11, 2001, terror attacks, which claimed the lives of 2,977 people at the World Trade Center, the Pentagon and Shanksville.