His father wanted to take a photo. The 9-year-old boy, hiking with his family in Mount Rainier National Park in Washington state on a summer day in 2012, leaned against a bridge railing above 72-foot Myrtle Falls.

The railing collapsed. The boy fell, plunging into the boulder-strewn gorge below, breaking his back, ribs and wrist. It took paramedics five hours to get him to a hospital.