Toluca, Mexico (CNN) - For decades, Richard St. Denis has advocated for the rights of Americans who, like him, are living with a disability.
But the attorney from Colorado saw his life shift in 1997, when he was invited to speak in Mexico.

"I was asked to bring one wheelchair to give to somebody," he remembers. "As I was waiting for the program to begin, I was shocked to see people using branches for crutches, being pushed in wheelbarrows and crawling."

The lone wheelchair went to Leti Elizale Marcial, a 17-year-old suffering from polio. She had never walked a day in her life, and she was carried around daily by her mother.

"I saw how happy she was, but I looked around and saw the other people that had nothing," St. Denis said. "Their life was going to be exactly the same, and one wheelchair was not enough. I just felt someone had to come and help."

So once a year from 1997 until 2004, St. Denis would load a van with 10 to 15 donated wheelchairs and drive 30 hours - from Colorado to Mexico - to distribute them to people with disabilities.

Now, he has a permanent residence in the country and a nonprofit,World Access Project, that provides custom-fit wheelchairs, walkers and canes to people in rural Mexican communities.

Read more on St. Denis here.