In the summer of 1968, the first ever Special Olympics was held at Soldier Field in Chicago.
The Special Olympics has since grown to become the largest sporting event for those with intellectual disabilities.
They are now held every two years in major cities around the world.
Witness went back to Soldier Field to speak to Frank Olivo, a competitor at the first Special Olympics, and Anne Burke, an organiser.
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Footage from 1968 courtesy of Special Olympics International. Story from BBC.COM