For those privileged few who have seen Earth from space, the very first thing they notice is the thin blue line of atmosphere that clings to our planet and sustains life. How our planet creates and regulates that oxygen is a mind-blowing story involving a flying river, a global dust storm, collapsing glaciers and the most important creature you've never heard of. It's an incredible chain of connections that reveal just how truly wondrous our home is. Everything connects, so life and planet breathe together. Astronaut host - Chris Hadfield