Certain images will be indelibly linked to the interstate bridge collapse: Mangled green steel beams, giant concrete slabs that seem to float on the Mississippi River, a school bus frozen on a downward slant. Even as the search for victims continues, historians are thinking about how to document the carnage.
Those who have chronicled other disasters say it's important to quickly secure artifacts, photographs and witness accounts that will convey the magnitude years from now. Key items would be lost forever by waiting too long, they say.

Minnesota Historical Society officials also want to be sensitive to the recovery and the investigation.
“We certainly don't want to be ghoulish or in any way disrespectful of the people who suffered in this tragedy,” said Jennifer Jones, head of the society's collections department. But, she added, “This is indisputably an important event in Minnesota history and in American history, in fact.”