13. Empress Anna of Russia

It feels safe to say that when Russians recall a leader's reign as a "dark era," we're into some deeply, deeply dark events. Empress Anna, a niece of Peter the (Not So) Great, had survived many humiliations before Russia's Supreme Privy Council elevated her to Empress; they thought she would be easy to control, but instead, her decade-long reign was characterized by Anna's cruelty and capriciousness. A career of personal vendettas was fueled by her limitless power and a secret police system she stood up to discover and end plots against her. Learn more about your ad choices. Visit megaphone.fm/adchoices