Amazon founder Jeff Bezos' ex-wife MacKenzie Scott once fixed a broken tooth with glue because she couldn't afford a dentist. Now she's giving $20 million to support struggling teenagers' mental health

• The donation to the non-profit organization Active Minds is the largest single gift in the charity's history.
• It comes at a critical time for American teenagers, with data from Fortune showing that nearly one in five adolescents now report having thoughts of self-harm.