The biggest earthquake to strike the nation of Haiti in 200 years has devastated the poorest country in the western hemisphere. The State Department says the human toll from the magnitude 7.0 quake is too great to measure. The Prime Minister of Haiti, Jean-Max Bellerive, estimated the death toll at hundreds of thousands. Other estimates put the death toll at a half million. President Obama has mobilized rescue efforts by the United States. Rachel Wolff is a spokeswoman for World Vision, an aid organization with workers in Haiti.