With the fall of the Soviet Union, the theoretical physicist Armen Sarkissian returned home and became first the Prime Minister and then the President of the newly reformed state of Armenia. In his book, The Small States Club: How Small Smart States Can Save the World, he argues that successful smaller nations have had to learn to be more agile, adaptive and cooperative, compared to the world’s ‘greater’ powers. The world map has changed considerably, especially in the 19th and 20th century, as empires fell apart and smaller nations fought for independence. The Canadian historian Margaret MacMillan looks back at this time, and considers how small states survive during times of conflict. In 2018 she presented the BBC’s Reith Lectures, The Mark of Cain, on the tangled history of war and society. The BBC’s Chief International Correspondent Lyse Doucet is no stranger to conflict in the world, as she has covered all the major stories across the Middle East and North Africa for the past two decades. But she is also interested in the way small states have been instrumental in mediating world conflicts, and punching above their weight on international issues like the climate crisis. Producer: Katy Hickman