PARIS — Hours after the world’s top men’s marathoners cross the finish of what is expected to be beautiful but brutal course, Paris Olympic organizers are doing something that’s never been done before: welcoming some 20,000 runners to the start line to tackle the race themselves.

Runners around the world earned their bibs for the Marathon Pour Tour (Marathon For All) by logging their work toward physical activity challenges over the last several months. Those who earned enough points were entered into a draw to secure one of the 20,024 spots up for grabs in the marathon. An additional 20,024 spots were also awarded for a 10km event, which will cover some of the same ground as the Olympic marathon course.