Two of the people behind the CNN Original series "Soundtracks: Songs That Defined History" Maro Chermayeff and Julia Marchesi from production company Show of Force, talk about what the series is about and what it took to get the show made. From interviews with Melissa Etheridge, David Crosby, Billy Joel, Smokey Robinson and more to what it's like working with Dwayne "The Rock" Johnson and Dany Garcia on a music series. Soundtracks: Songs That Defined History is an eight-part CNN Original Series premiering Thursday April 20th at 10pm. Soundtracks is produced by Show of Force and Seven Bucks Productions.