Sue Klebold's son Dylan was one of the two shooters at Columbine High School. Nearly 20 years later, she talks about her struggle to understand his actions, and to find forgiveness.

Tom Stranger raped Thordis Elva when they were dating in high school. Years later, they started a painful and painstaking dialogue about accountability and reconciliation.

Before donating bone marrow to her sister -- Elizabeth Lesser and her sister undertook a process of seeking forgiveness from each other. She says forgiveness is hard but necessary for our well-being.