The death penalty is the ultimate punishment, often shrouded in secrecy. In 2007, at least 1,252 people were executed in 24 countries, according to Amnesty International. Nearly 90 percent of these recorded executions -- believed to be just a fraction of the true number -- were in five countries: China, Iran, Saudi Arabia, Pakistan and the United States. In 2007, three countries, Iran, Saudi Arabia and Yemen, violated international law by executing people for crimes committed when they were younger than 18, according to Amnesty. Up to 27,500 are estimated to be awaiting execution on death row around the world.

But the world is moving inexorably towards abolition. In a historic December 2007 resolution, the UN General Assembly called on all nations to abolish the death penalty. To date, 137 countries have done this either in law or practice.