ABC News' Diane Sawyer spoke with Grace Danahy, whose father lost his life during the Sept. 11, 2001, terror attack on the World Trade Center, before his daughter was born. ▻ ↧ 9/11 25th anniversary live updates: Families gather for ceremonies ... 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.