Slavery is illegal in every country in the modern world. Mauritania was the last country to make slavery illegal, which it did in 1980. Although slavery has been outlawed, it still exists; even on the narrowest definition of slavery it's likely that there are far more slaves now than there were victims of the Atlantic slave trade.
Richard Re, writing in 2002, stated:
Conservative estimates indicate that at least 27 million people, in places as diverse as Nigeria, Indonesia, and Brazil, live in conditions of forced bondage. Some sources believe the actual figures are 10 times as large.
Modern slavery differs from historical slavery in several ways:
* There are more slaves than ever before, but they are a smaller proportion of the human race
* No-one seriously defends slavery any more
* Slavery is illegal everywhere and so requires corruption and crime to continue. The power of the slave owner is always subject to the power of the state; slavery can only continue to exist if governments permit it to, and some writers claim that government corruption is a leading cause of the persistence of slavery
* Slaves are cheaper than ever and can generate high economic returns. Modern slavery is very cheap, and Kevin Bales has argued that this has made modern slavery even worse than that of Atlantic Slave Trade:
In the United States before the Civil War, the average slave cost the equivalent of about fifty thousand dollars. I'm not sure what the average price of a slave is today, but it can't be more than fifty or sixty dollars.
I think that the cost of a slave is a telling figure, if it they were rare and slave owners properly persecuted then the price would reflect that. Still on a related BBC page it is gratifying to see whose fault it isn't:
While Islamic law does allow slavery under certain conditions, it's almost inconceivable that those conditions could ever occur in today's world, and so slavery is effectively illegal in modern Islam. Muslim countries also use secular law to prohibit slavery.
News stories do continue to report occasional instances of slavery in a few Muslim countries, but these are usually denied by the authorities concerned.