Almost 20 years after Columbine, what’s changed and what hasn’t

The end of this week will mark 20 years since the tragedy at Columbine. NBC’s Kate Snow takes a look at what's changed and what hasn't through the eyes of parents who know all too well.

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About NBC Nightly News with Lester Holt

Watch "NBC Nightly News with Lester Holt," providing reports and analysis of the day's most newsworthy national and international events. See More

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