Only 5,000 people a year visit “the hermit kingdom” of North Korea. Among them has been the radio producer Sarah Jane Hall, who first went in 2004, when, she says, it was hard to imagine the political temperature could get any higher. Since then, of course, the leaders of the United States and North Korea have been threatening each other with nuclear weapons. In Archive on 4: Travels in North Korea, which was broadcast on Saturday evening and is now available on the BBC iPlayer, Hall asks: “Is it easier to go to war with a country we don’t understand?” She mingles her own experience of North Korea with those of recent visitors to the country, including tour leaders and their customers, a diplomat, a film-maker and the broadcaster Andy Kershaw. What did they see and do, and what did they learn?