Well, I'd need a certainty that i would be horribly rich. And I'd need to be injected with language skills .... And then I'd go to the time of:
Catherine the Great. I'd seduce Orlov and snatch that diamond for me. Then I'd travel to France, see Marie Antoinette before she looses her head. And then I'd travel to England, see whats happening there and retire in Scotland, the most beautiful country ever.