Episode description
This week how American cities like San Francisco became safe havens for undocumented immigrants, the story of Tilikum and first recorded killing of a human by an orca whale, discovering DNA, the ship wreck that gave locals whiskey galore and Kenya's smash hit song - that got everyone singing in Swahili.
(Photo: Supporters of Sanctuary Cities demonstrating in San Francisco, January 2017. Credit: AP)