Retired from tennis, Martina Navratilova continues to push herself, and to use her gifts to inspire and help others.

With a tennis racket strapped tightly to her hiking pack, Martina Navratilova began her ascent of Mount Kilimanjaro. The tennis legend had visions of celebrating at the summit of Africa’s highest peak by hitting a couple balls to see how far they might fly in the thin air at 19,341 feet.

Thirty years after a dream eluded her, swimmer Diana Nyad is out to show the world what commitment looks like.

More than 90 miles of open ocean lies between Cuba and South Florida. For Diana Nyad, that stretch of shark-infested water equates to about 65 continuous hours of solitude, if all goes well—no rest, no physical contact with another person, no sound or movement except for the rhythmic kick-stroke-breathe, kick-stroke-breathe. Nyad, 61, is swimming every inch of this journey without assistance… or a shark cage.