Netflix’s upcoming film The Swimmers tells the remarkable true story of two Syrian sisters who fled their war-torn home in Damascus and went on to compete in the 2016 Rio Olympic Games.

In 2016, two sisters by the names of Sarah and Yusra Mardini competed at the Rio Olympic Games. But that the pair were related and on the same team wasn’t by half the most remarkable thing about their participation in the biggest sporting event in the world.