The Crossing

At 7:59 a.m. on Dec. 14, 1961, a passenger train smashed into a school bus in the farm country of Weld County, instantly killing 20 children.

It was the deadliest traffic accident in Colorado history, leaving behind 17 survivors and a devastated community.

Forty-five years later, the stories of those who lived and those who mourned show how a single moment has the power to uncoil through decades, shaping people for the rest of their lives.

Here's the first part. (Thanks Justin)