It's what is known as a defining moment. You know where you were when you first heard of it. I recall the day the space shuttle Challenger exploded. I was in high school, sitting in English class when somehow the news came in. We stopped whatever we were doing and discussed the events that were occurring. The teacher was crying, as were several of my classmates. The teacher took it particularly hard as she felt a kinship of sorts with Christa McAuliffe, the first teacher and civilian in space. All 7 crew members were killed when the still intact crew compartment collided with the surface of the ocean. Fragments of the Challenger were recovered from the ocean floor and washed up on Florida beaches. President Ronald Reagan said that evening in his speech to the nation, " We will never forget them, nor the last time we saw them, this morning, as they prepared for their journey and waved goodbye and "slipped the surly bonds of earth" to "touch the face of God." The memory of that day is seared into the collective consciousness, just like the flaming Twin Towers on September 11, 2001 or President Kennedy's motorcade in Dallas.