- BethAnn Telford, 47, will run seven marathons in seven days on seven continents
- Telford was diagnosed with brain cancer in 2005
- Her goal is to raise $1 million to support brain cancer research
(CNN)For the past three years, BethAnn Telford has trained for a grueling athletic achievement, the World Marathon Challenge. It's seven marathons on seven continents over seven days. An ambitious goal, but not her biggest challenge.