Story highlights Chau Smith, 70, of Missouri, enjoys challenging herself

"All my life ... I always did crazy things," she says

(CNN) Running four marathons in five weeks wasn't enough. Running 10 marathons in a year wasn't enough. Running more than 70 marathons during her lifetime wasn't enough.

Seventy-year-old Chau Smith wanted to challenge herself even further, so she decided to run seven marathons in seven days on seven continents. In January, the Missouri woman accomplished that goal.

Between January 25 and January 31, Smith ran marathons in Perth, Australia; Singapore; Cairo; Amsterdam; Garden City, New York; Punta Arenas, Chile; and King George Island, Antarctica. Each day, Smith woke up and ran 26.2 miles. Then she'd get on a plane and fly to the next destination to do it all over again.

Despite her marathon training, Chau Smith still works 10-hour days.

"She didn't want to publicize this before doing it," said Steve Hibbs, owner of the specialty travel company Marathon Adventures, which organized the trip. "She overcame a lot, and it was just really impressive to see her run and complete the event."

Nine other people joined Smith in running on all seven continents. Although she had done many marathons before, training to run seven in a row took months.

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