The hidden base that could have ended the world

In the 1970s and 80s, crews sat at constant readiness in nuclear missile silos buried in the Arizona desert. What would have happened if they had got the order to launch? By Richard Hollingham.
Read more: http://www.bbc.com/future/story/20160729-the-hidden-base-that-could-have-ended-the-world?source=Snapzu