Yo-Yo Ma, Gabby Giffords honor lives lost to gun violence

NewsHour profiled former Rep. Gabby Giffords’ journey to "retrain her brain" after she was shot in 2011. Part of her routine includes playing her childhood instrument, the French horn. That piece caught the eye of cellist Yo-Yo Ma, who then reached out to Giffords to play together. Watch now as they rehearse Simon and Garfunkel's "The Sound of Silence" to honor the lives lost to gun violence.