Where/When would you go and why? The ethical bit - while we are all familiar with the idea that time travel could result in changes in a future - the going back and killing one's grandfather debate - I propose the 4th Wall theory, as shown slightly in a Star Trek Next Generation episode - you can observe but cannot interact or influence history. Ethical time travel - it could work! I would like to go back to: 5th December 63 BC to ancient Rome where Julius Caesar, Cicero and Cato the Younger were debating about what to do about senatorial colleagues accused of involvement in a plot to overthrow the government (the infamous Catilinarian Conspiracy) - all the boys there, except Pompey. I would like to see England on a day in the middle ages (see the plague for real?), see George Washington in real life or even walk through London a hundred years ago... What about you?