Future. Not sure when and where. If I would be able when it'll happen, I would time-wrap to apocalypse or Judgment Day to see how everything will end. Or perhaps, see how humans exodus Earth or stuffs.
Then I'd go to about 200 years into the future, and see whether it was a wasteland of distopian hell or a golden age of the colonisation of the rest of the solar system. That aught to be about right given the pace of computing so far.
Of course, then I'd come back with some fancy headgear and a tank, patent it, become very rich indeed, and chill.