It has been almost a month since Israel and the US launched their war against Iran, and already there have been strikes in more than a dozen countries, with reports of over 2,000 people killed across the region. As the war drags on and more countries get involved, there are concerns this conflict could escalate into something truly global.

We speak to emeritus professor of International History at the University of Oxford, Margaret MacMillan, and explore how world wars start, how they end and what can be done to avoid them.

Producers: Chris Benderev and Lucy Pawle

Executive producer: James Shield

Sound engineer: Travis Evans

Senior news editor: China Collins

(Photo: US Military aircraft perform 4th of July flyover past New York City and New Jersey, 4 July 2020. Credit: Mike Segar/Reuters)