參考答案: Feb 1st, 2003, "Communication was lost with the space shuttle Columbia ?8 a.m. Central Time." Space shuttle Columbia breaks up during re-entry, killing all 7 crew members. President George W. Bush tells the grieving families:" You're not lone, our entire nation grieves with you, and those you loved, will always have the respect and gratitude of this country." 1968, in one of the Vietnam War's most searing images, Saigon's police chief executes a Viet Cong officer with a pistol shot to the head. 1979, Iran's Ayatollah Khomeini receives a tumultuous welcome as he arrives in Tehran ending nearly 15 years in exile. And 2004, singer Janet Jackson's breast is exposed during the Super Bowl halftime show, her partner on stage Justin Timberlake blames what he calls a "wardrobe malfunction".