If you grew up watching TV in the 80s, you only knew the 'Big Three' networks: ABC, NBC, and CBS. But in 1986 came something we hadn't seen in thirty years: a legitimate fourth network.

Welcome to the final episode of a three-part mini-series that looks back on the rapidly changing world of television in the 1980s.

In part three, we look at the creation and launch of Fox, a network that started from scratch, but, in just a few short years, gave the big networks a run for their money.

We'll look back at Fox's similarities with another fourth network from the 1950s -- The Dumont -- and how, thanks to shows like  Married...With Children and The Simpsons, Fox managed to break through in a big way.