'They think I'm crazy!' - globe-trotting grandma hunts down phenomenal marathon challenge

An ambitious group of American runners are setting off on an unfathomable quest, aiming to complete eight marathons, on eight continents in eight days.

Chau Smith, 71, wants to complete eight marathons, on eight continents, in eight days. Source: 1 NEWS

Among them is globe-trotting grandmother Chau Smith, who at the age of 71 isn't letting her age get in the way of achieving the remarkable.

Having run, seven marathons across seven continents in seven days last year, the Vietnamese immigrant is looking to go one better, undaunted by the challenge.

"When we had the triple 7 I said why not, and then triple 8. I'm not going to get any younger!" she told 1 NEWS.

"Think I'm crazy, but ya know from a little girl I've always done things so differently."

"We're tough people. We set our minds to do something we will finish." 

Racing for the epic challenge sees the team of five compete in Auckland, before heading to Australia, Singapore, Egypt, the Netherlands, New York, Chile and finally Antarctica.

Running for each marathon will begin at 5am, finishing at 9am, leaving the afternoon to allow the racers to travel.