Superthief Carmen Sandiego has stolen a time machine, and then nabbed an electromagnet from the year 2101. Now she's impersonating Roman Emperor (and Stoic philosopher) Marcus Aurelius, so she can use Hannibal's elephants and her electromagnet to steal the Colosseum.
The time-travel episodes of Where In The World Is Carmen Sandiego are pure win, especially the idea of Carmen impersonating Marcus Aurelius without anybody noticing. And I love that Ivy, the detective sent to track down Carmen along with her snot-nosed brother, manages to pwn this massive dude in the Arena. "Goddess of strength," indeed. Why don't more time-traveling villains come up with such amazingly byzantine schemes?