visit each continent

I heard about someone else who’s done this, so I’m wanting to do it, too.
I’ve got three, maybe four, (N and S America, Europe, Asia). I say ‘maybe four’ because I was in Istanbul, on the East side, which is technically Asia, but I don’t really feel like I’ve been to Asia.
I’m going to Cambodia this year, possibly.
Then I’ve still got Australia, Africa, and Antarctica left.