The first ever meeting between a sitting US president and a North Korean leader marked a de facto recognition of the North Korean regime. But it's still far from bringing lasting peace to the peninsula. What will it take to denuclearise North Korea? What do Koreans want? What do neighbours China and Japan want? What does Donald Trump want? And what are the prospects for the people in Pyongyang? Is it the first step towards the opening up of one of the world's most reclusive regimes?