When WWI began in 1914, few could predict its costs: With around 10 million soldiers and sailors killed and almost as many civilians, the world had never before seen such carnage. The economic costs were even higher: $186 billion was spent directly on war costs (around $2 trillion in today’s money). The human and economic consequences of the war meant that the costs didn’t end in 1918.

WWII was even more devastating than the WWI. Although we may never establish the precise figures, some 20-25 million servicemen were killed alongside an unimaginable 50 or 60 million civilians. In this episode we account for these devastating figures, looking at the global experience of the war including the Holocaust and Japanese war crimes, and examine the economic cost and its legacies.

The Cold War conflict between capitalism and communism had one key hotspot above all others: the Vietnam War. It cost of up to 4 million lives on both sides and saw a US expediture of around $200 billion in direct and indirect costs. But greater wealth didn’t translate into victory. This episode explores the paradoxes and terrible costs of this war. some of which are still being paid today.

Since 1978 a series of conflicts involving the USSR, the USA and other European partners as well as domestic militias, warlords and the Taliban has kept the Afghan people in a state of ongoing war, suffering and hardship. Foreign intervention has actually made life in Afghanistan worse in some ways. This episode explores the human and economic costs of this decades long conflict on all sides.

Overthrowing Saddam Hussein in 2003 was reasonably easy. Ending the violence in Iraq was not. In fact, war in Iraq ground on for more than a decade and its costs were enormous: the US spent more than $3 trillion overall. We trace the costs of war in the region dating back to the Iran-Iraq war and the Gulf War, and look at the cycle of violence which has devastated the country and its people.

9/11 marked a new era in global terrorism, and a "War on Terror" was launched by the US. Since then, trillions have been spent on conventional warfare, counter-terrorism, secret intelligence, homeland security, cyberdefence and more, in pursuit of a sometimes indefinable enemy. We look at the costs and impact of this effort. Is there less terrorism today than before 9/11? Is our world any safer?