How teachers are keeping the lessons of 9/11 alive for a new generation of students

Des Moines, Iowa — In West Des Moines, Iowa, roughly 1,100 miles from Ground Zero, history teacher Ann Krois is tackling one of the most defining moments of the past half century.

"Teaching students about 9/11 is critical," Krois told CBS News. "I want them to understand what their previous generation experienced, that trauma, and how an event like that brought millions of people, not even just in the United States, but globally, together."

Krois was in the third grade and had never even seen a skyscraper when terrorists turned four airplanes into weapons, killing almost 3,000 innocent people — a catastrophe that's now history class for eleventh graders like Fitz Carpenter.

"I actually learned some new stuff. I didn't know how many people were evacuated on the boats," Carpenter said.