This six-part series, hosted by the popular American science author and media theorist, Steven Johnson, explores the power and the legacy of great ideas. Topics explored in the series include why and how ideas happen, and their sometimes unintended results, including how the search for clean water opened the way to invention of the iPhone, and how the nagging problem of overheating in a New York printing business led to the invention of air conditioning, which inspired mass migration and a political transformation.