Nasa's Space Twins
Nasa astronauts Mark and Scott Kelly are the only twins who have both flown into space. They share the exhilaration of re-entering the earth's atmosphere. And they remember the trauma of the 2011 gun attack on Mark's wife Congresswoman Gabrielle Giffords.
Mexican artists - and brothers - Ivan Puig and Andres Padilla Domene tell us how they built a special car to explore hundreds of miles of disused rail track. Along the way they photographed ruins and recorded people's stories.
Turkish pianist Idil Biret was a child prodigy in the 1940s and an international soloist by the age of sixteen. She shares memories with the BBC's Nicki Paxman.
From Islamabad, we hear the story of Mohammed Ayub, who has been teaching street children in a city park for nearly 30 years.
(Photo: Courtesy of Nasa)