Four years after his last visit, Martin Geissler returns to Dadaab refugee camp in Kenya to visit Minhaj, a one-year-old boy who was on the verge of death from malnutrition. To find out about America's complex relationship with its nuclear legacy, Alok Jha travels to the Nevada desert, where in the post-war era the US government performed thousands of above-ground atom bomb tests. Rageh Omaar is in Beirut, Lebanon's cosmopolitan capital which stands in contrast to the scenes of war and terror on the country's borders.