In the final episode of this landmark series charting the history of human civilisation, Andrew Marr brings the story right up to date with the twentieth century.Marr suggests that humanity found itself propelled forward by our technological brilliance but limited by the consequences of our political idiocy. Democracy confronted communism and fascism, and two world wars would underscore our political failures more than ever before.But our achievements were also astonishing, especially in the fields of science and technology. We invented machines of awesome speed and power, and reached beyond the limits of our planet. Now, more of us live longer, healthier and wealthier lives than our ancestors could ever have imagined.But Marr argues that with seven billion of us on the planet, and rising fast, either we manage the earth's natural resources better or we risk global catastrophe. The decisions we make in the next 50 years, he argues, may well decide our fate. For Marr, the most interesting part of human history lies just ahead.