Dan Carlin’s Hardcore History
You can find it here.
Little introduction is required with Dan Carlin’s series, it’s incredibly well know thanks to the mind boggling amount of information and effort put into each podcast. I should warn that only some of these are free but they’re well worth the listen and if you find yourself opening your wallet, do go for the Mongol series first. It’s just about the best listening experience you can have. Each podcast covers an event in history that you might not know about (eg. the day Martin Luther changed the world and the course of the city of Munster) or even some you do such as the story of 300 as told by the Persian side.