When producers came up with the title `Big History' for this programme they weren't thinking big, they were thinking really big. The show presents a grand theory postulating that every event throughout history is connected. Each episode begins with a traditional historic topic - like the American Revolution - before weaving together insights and evidence from other fields, including astronomy, chemistry and economics. In the end, the show puts together the puzzle pieces from 16 half-hour episodes and, in a two-hour finale, creates one grand narrative that reveals the unifying link among all events. Emmy-winning actor Bryan Cranston serves as narrator to, as he puts it, `be the voice of 13.7 billion years of history'.