Relentless

The World Marathon Challenge?seven marathons on seven continents in seven days?is the ultimate race for adventurous runners. It tests the athletes to their limits, going from biting cold Antarctic conditions one day to dry desert heat another. To survive the onslaught of sensations?fear, fatigue, depression, elation?takes a special sort of determination and strength of will. Few would voluntarily take on such a challenge, and fewer still would finish it.