Habitat for Humanity International(which can be abbreviated to "Habitat for Humanity" or just 
"Habitat") is a non-governmental, non-profit, Christian organization that builds houses for 
underprivileged families. It was founded in 1967 by Millard and Linda Fuller in Americus, Georgia. 
They wanted to find a way to use their overabundance of money to help the poor families that 
couldn't afford a decent place to stay.
    Habitat for Humanity is an organization made up mostly of volunteers that help build homes for 
families that wouldn't normally be able to afford a house. The main reasons that Habitat is able to 
offer these houses at such a low price is becuse many of the workers are volunteers and because the 
houses are built with no profit added and no interest charged. The main way that they have gained 
enough money to afford their expanding organization is through generous donations from wealthy 
people around the world.    
    Even though the organization began in the United States, they are currently working in over 
100 different countries. By 2004 Habitat had built 50,000 houses inside the United States and over 
175,000 around the world, and in 2005 Habitat built its 200,000th house, bringing the number of 
people sheltered around the world to 1,000,000 people. 
    One of the most important problems that Habitat helped with(and is still helping with) was when 
the hurricanes Katrina and Rita struck the coast of the Gulf of Mexico. As soon as they could, 
volunteers from Habitat imediately went down to the gulf coast and began helping families put their 
lives back together. It is a tough job and Habitat doesn't plan on leaving until they've helped 
every person that they can.

For more information: Official Habitat for Humanity International website wikipedia: Habitat for Humanity International

Workers build the exterior wall of a house in Zaire in 1975 Picture from: http://www.habitat.org/how/historytext.aspx