Much of human history has been defined by the actions of around 50 to 70 empires that once ruled large swathes of people across vast chunks of the globe. Each of these empires, whether large or small, for ill or for good, has influenced world history. It’s hard to say which has had the greatest impact on society — it is, after all, somewhat subjective and hard to measure — but some have undeniably shaped the course of human history, forever and irrevocably. Here are six such empires, from the mighty Persians to the globe-spanning British. Persian EmpireAround 550 BCE,...