Marianne Bohr and her husband, about to turn sixty, are restless for adventure. They decide on an extended, desolate trek across the French island of Corsica--the GR20, Europe's toughest long-distance footpath--to challenge what it means to grow old. Part travelogue, part buddy story, part memoir, The Twenty is a journey across a rugged island of stunning beauty little known outside Europe.    From a chubby, non-athletic child, Bohr grew into a fit, athletic person with an "I'll show them" attitude. But hiking The Twenty forces her to transform a lifetime of hard-won achievements into acceptance of her body and its limitations. The difficult journey across a remote island provides the crucible for exploring what it means to be an aging woman in a youth-focused culture, a physically fit person whose limitations are getting the best of her, and the partner of a husband who is growing old with her. More than a hiking tale, The Twenty is a moving story infused with humor about hiking, aging, accepting life's finite journey, and the intimacy of a long-term marriage--set against the breathtaking beauty of Corsica's rugged countryside.