Hundreds of thousands of Haitians were still waiting desperately for aid Sunday, while rescue workers continued to pull people from collapsed buildings five days after an earthquake ravaged Port-au-Prince. World leaders vowed to help the impoverished nation rebuild.

President Barack Obama joined predecessors George W. Bush and Bill Clinton at the White House Saturday to announce a fundraising appeal to benefit Haiti in "one of the largest relief efforts in our history," Mr. Obama said.

As Haiti struggles to recover from a devastating earthquake, Haiti's ambassador to the United States, Raymond Joseph, is confident that his country will find a way to rebound from the disaster with the help of the U.S. and other international organizations.

Haiti's earthquake was "a catastrophe of monumental proportions," describes Nick Birnback of the U.N. Department of Peacekeeping Operations. The Caribbean nation was still mending from a series of major storms in 2008 and deep-seated political problems when the quake struck.

Despair has begun to give way to anger in Haiti, as countless victims of the devastating earthquake awoke Friday still waiting on humanitarian aid that continues to be slowed by a broad array of complications. Even as the first U.S. Navy ship, the USS Higgins, arrived Thursday, as well as transport planes from China and Belgium, frustration built throughout the island nation.

A look at the rescue efforts and fight for survival in Haiti.

Up to 50,000 Americans live in Haiti, and six are now confirmed dead with many more missing. Bill Neely of ITN has more on how U.S. citizens have been affected.

Kwame Holman reports on how the United States is responding to help Haiti, and then Jeffrey Brown talks to a Los Angeles Times reporter about international efforts on the ground.

Raisingthe alarm about the urgent need to address health issues.

Developing nations will begin receiving donated H1N1 vaccine Thursday, just as the U.S. shortage is waning and some European nations find themselves with more vaccine than they can handle.

Has the rush to get vaccinated slowed too soon?

Global Post looks at the ailing profession of psychiatry in India.

In the next installment of his series on Mexico, Ray Suarez examines how the government is using cash incentives to improve the health of the nation's poorest, and inspiring nations throughout the world to do the same.

Getting paid to keep your family healthy? That's the idea behind Mexico's innovative conditional cash transfer program, Oportunidades, which gives cash payouts to parents who take steps to keep themselves and their children well. Ray Suarez reports from rural Morelos on how the program works, what critics say about its weaknesses and why it has become an important model in this global recession.

Getting paid to keep your family healthy? That's the idea behind Mexico's innovative conditional cash transfer program, Oportunidades, which gives cash payouts to parents who take steps to keep themselves and their children well. Ray Suarez reports from rural Morelos.

A web exclusive look at the business of medical tourism. Ray Suarez preview's his report on Americans traveling to, or moving to, Mexico to avoid steep healthcare costs.

Thousands of Americans are increasingly traveling to resort towns like Puerto Vallarta, in Mexico, not for vacation, but for the cheap health care. In many cases, reports Ray Suarez, for care they couldn't afford in the United States.

While there may be debate over what's causing global climate change, there are far fewer questions about the effect of a warming planet on human health, reports Ray Suarez.

Judy Woodruff asks two experts to weigh the outcome of the non-binding agreement reached Friday at the international climate summit in Copenhagen.

President Barack Obama told world leaders Friday that it was time to come together on a climate change agreement, calling out stubborn positions that have stood in the way of progress, namely between rich and poorer countries.