Everyone alive during the event remembers the moment they found out about it -- where were you?
The most harrowing Challenger fact from Wikipedia:
The crew cabin, made of reinforced aluminum, was a particularly robust section of the orbiter. During vehicle breakup, it detached in one piece and slowly tumbled into a ballistic arc. NASA estimated the load factor at separation to be between 12 and 20 g; within two seconds it had already dropped to below 4 g and within 10 seconds the cabin was in free fall. The forces involved at this stage were probably insufficient to cause major injury.
At least some of the crew were probably alive and at least briefly conscious after the breakup, as three of the four recovered Personal Egress Air Packs (PEAPs) on the flight deck were found to have been activated. Investigators found their remaining unused air supply consistent with the expected consumption during the 2 minute 45 second post-breakup trajectory.