Japan was great, and I highly recommend it! Loved Greece as well. (I was a bit more meh on Paris, though admittedly I was a very tired teenager at that point [it was at the end of a long trip], and I probably wasn't giving it a fair shake.)

Ironically, considering how close they are, I've never been to any of the US National Parks OK I guess both Mammoth Cave and Hot Springs, AK are national parks? But I've never been to any of the really famous ones.