Supplementary Convention on the Abolition of Slavery entered into force.

The Supplementary Convention on the Abolition of Slavery, the full title of which is the Supplementary Convention on the Abolition of Slavery, the Slave Trade, and Institutions and Practices Similar to Slavery, is a 1956 United Nations treaty which builds upon the 1926 Slavery Convention, which is still operative and which proposed to secure the abolition of slavery and of the slave trade, and the Forced Labour Convention of 1930, which banned forced or compulsory labour, by banning debt bondage, serfdom, child marriage, servile marriage, and child servitude.