John Cena is a WWE 17-time World Champion wrestler, bestselling author, and actor whose on-screen career includes installments of the “Fast & Furious” franchise, “The Suicide Squad,” and its spinoff series “Peacemaker.”

Edward Snowden is an American whistleblower who copied and leaked highly classified information from the National Security Agency in 2013 when he was a Central Intelligence Agency employee and subcontractor. His new book "Permanent Record" is now available.

Professor Brian Cox is an English physicist and Professor of Particle Physics in the School of Physics and Astronomy at the University of Manchester in the UK.