CNN traveled to Mauritania, where we found the shackles of slavery are mental as well as physical. And breaking them requires unlikely allies. More about 'Slavery's Last Stronghold'

Documentary airs on CNN International TV:

– Thursday, March 29, 3:30 a.m. ET
– Friday, March 30, 12:30 a.m. ET
– Saturday, March 31, 2:30 a.m. and 11 p.m. ET
– Sunday, April 22, 2:30 a.m. and 11 p.m. ET