How a letter and a wheelchair reshaped the Boston Marathon

Fifty years ago, Bob Hall changed the course of marathon history with a simple letter and a modified hospital wheelchair.

In 1975, the 23-year-old, who had been diagnosed with polio as an infant, asked Boston Marathon race director Will Cloney if he could compete using a wheelchair. Though hesitant about officially registering him, Cloney offered Hall a challenge: finish in under three hours, and he'd receive a certificate.

"I said, I'm all set," recalls Hall, who completed the course in 2 hours and 58 minutes, becoming the first official wheelchair athlete in Boston Marathon history.