At the age of 14, Hugh Evans spent a night with cockroaches crawling all over him.

That experience turned out to be life-changing for Evans, now 30. Far removed from his comfortable home in Australia, he traveled to the Philippines with an aid organization that set him up with a host family. Their home was in Smokey Mountain, a teeming slum in Manila. A boy in the family, Sonny Boy, was the same age as Evans. The disparity between their lives struck him hard.

"I had an epiphany that I wanted to commit my life to this," said Evans. "I want to see an end to extreme poverty in my lifetime."

It's the same goal shared by global organizations and world leaders, and some remarkable progress has been made in reducing the numbers of the world's poorest. In 1981, about half the developing world lived in extreme poverty. By 2010, it had fallen to about 20 percent. The figures were tallied by the World Bank, which defines extreme poverty as living on less than $1.25 a day. The organization has set 2030 as the goal to reduce the rate even further, to 3 percent.

Despite the low threshold in defining extreme poverty, it still means 1.2 billion people around the world scrape by on that meager amount.

The gains worldwide are uneven. China and Southeast Asia have made huge strides in lifting their populations above that line. But the opposite is true in Sub-Saharan Africa. Even though economic growth is surging across the continent, the number of extremely poor people actually increased over the last three decades.

So what does it mean to subsist on $1.25? Following his epiphany in the Manila slum, Evans founded The Global Poverty Project to raise awareness about the issue of extreme poverty.

The organization's campaign, "Live Below the Line," hoped for an even greater impact by actually having people eat the way that the world's poorest must do every day. Adjusted for U.S. purchasing power, the campaign allows participants to spend $1.50 a day for five days.

"For us, it's a lot easier, we're doing it just for food and drink," said Evans. "For the world's poor, they're doing it for food, housing, education, health care, everything they might need in life." Evans has taken the challenge for three years, noting, "By day five last year, I was eating rotten bananas."

He is joined this year by 15,000 people worldwide, including celebrities such as Ben Affleck and Josh Groban, as well as other notables, such as Jill Biden and Hunter Biden, the vice president's son. He said the campaign will raise up to $4 million for various aid organizations working to help the world's poorest.

"Extreme poverty is the sort of useless suffering where a child might die for lack of a 30-cent immunization," said Evans. "The world has enough food to feed everyone one-and-a-half-times over. It's really about: How does everyone access that food?"

That lack of food can impact not only individual lives and communities, but entire nations, said Evans, citing a link between malnutrition and stunted brain development, which affects children's abilities to learn in school.

"What we need to see, I believe, is the sort of aid that focuses on health and education that allows people to lift themselves out of poverty, coupled with access to markets and trade," said Evans. "I was born in 1983. So in my lifetime, extreme poverty was halved. In the rest of my life, I think we could end it altogether."