Jolyon Jenkins explores Esperanto, the language designed to bring world peace and harmony. Invented in the late 19th century, Esperanto is simple to learn, with a logical grammar, a vocabulary drawn from European languages, and no irregularities. Its creator, Ludovic Zamenhof, hoped that it would become a second language that everyone could speak, eliminating international misunderstandings. For a while, Esperanto flourished, and there was even a tiny Esperanto-speaking state in what is now Belgium, but both Stalin and Hitler saw it as subversive and tried to crush it. Jolyon tries to learn the language and to discover what remains of those early ideals. He finds elderly Esperantists playing word games in a Cardiff pub, Brazilian spiritists who believe that Esperanto is the language in which the dead converse, and a small Esperanto-speaking enclave in Goma, in the war-torn eastern Democratic Republic of Congo (some of whom learned it under the misapprehension that Esperanto was an organisation that handed out money). Is Esperanto a blindingly obvious and sensible idea, or a ludicrously utopian one? Presenter/producer: Jolyon Jenkins.