Much of the history of the past 200 years revolved around a single idea called "socialism." At its crest in the 1970s, roughly 60 percent of the earth's population lived under governments that espoused the socialist ideal in one form or another. Then suddenly, it all collapsed. Why? Socialism's meteoric rise and spectacular fall are explored in this three-hour PBS documentary miniseries. Heaven on Earth traces socialism's evolution through a series of compelling profiles of the movement's most important figures: Karl Marx and Friedrich Engels, Eduard Bernstein, Samuel Gompers, Clement Attlee, Tanzania's Julius Nyerere, Deng Xiaoping, Mikhail Gorbachev, Tony Blair and the man who first coined the term "socialism," Robert Owen. Join host Ben Wattenberg for the chronicle of a movement that rivaled the great religions in sweep and power, but ultimately failed to deliver the "Heaven on Earth" promised by its most ambitious advocates. Bonus Material: Ben Wattenberg, Heaven on Earth author Joshua Muravchik and founding editor of The New Left Review Norman Birnbaum discusses the past, present and future of socialism on a special edition of the PBS series Think Tank with Ben Wattenberg.