The truce camp at Panmunjom on the Korean peninsula must rank among the world’s most surreal sights. Helmeted soldiers in forest-green uniforms clench fists with staged aggression as tourists take snaps (army-regulation dark glasses are a mainstay in the souvenir shop). Beyond the sky-blue UN huts, brown-uniformed North Korean troops peer back through binoculars. Despite its absurd theatricality, this is a volatile point of contact in an unfinished war: the two Koreas never signed a peace treaty after the Korean War of 1950–53. A couple of days before I visited in March, the North had fired another ballistic missile off the coast, in defiance of UN bans. 

Over the last 60 years the heavily fortified, 155-mile-long Demilitarised Zone (DMZ) has become a wildlife sanctuary where ginseng farmers get rich and Manchurian cranes peck at paddy fields. But the frontier haunts Korean society. Of the million families it divided, up to a third are still separated. At a