(CNN) At the heart of the deadliest migrant route in the world, a small number of rescue boats brave the choppy waters of the winter Mediterranean. They are picking up stranded migrants attempting to cross from Africa to Europe, with many telling horror stories of imprisonment, brutality and exploitation as they had passed through Libya.

'Killed like animals'

Detention and physical violence

Evacuating detention centers

'We slept on the floor and they raped the women'

The end of the nightmare