Listen now 55 mins
Daryl Davis, an African-American musician, explains how he made friends with members of the Ku Klux Klan - and even managed to persuade some of them to leave the organisation.
Also on the programme, professor Lonnie Thompson, an ice investigator who has spent nearly 40 years leading teams drilling into the ice, to remove huge cylinders of frozen water in order to look deep into the Earth's history.
Tunisian street artist, Karim Jabbari talks about painting a mural on the wall of the prison where his father was held. And, we hear from a Somali lawyer who tracked down the man who had tortured him and won a landmark case against him.