In 1807 Congress passed a law banning the importation of slaves to the United States. The law went into effect on January 1, 1808. This act ended large-scale importations of slaves into the United States. In the eight years before the law made the trade illegal, the United States imported about forty thousand new slaves from Africa. From 1808 until the Civil War broke out in 1861, less than a fifth of that number of slaves would be illegally smuggled into the nation. The law thus ended American participation in one of the most immoral violations of human rights in world history. The law did not, of course, end slavery itself in the United States. That would not take place until the Civil War and the adoption of the Thirteenth Amendment in 1865 ended all slavery in the nation.