Since these are the 10 most visited countries (with France being the biggest tourist magnet), there is a good chance to do well in this list. But don't be sad if you don't get to tick many boxes:
UNESCO world heritage sites can mean two things for us travelers. It's either a recommendation to visit a place for its immense cultural value - or to leave it alone to protect its natural treasures.
It's often surprising what's listed by UNESCO and what's not - Neuschwanstein castle, for example, is still waiting for admission. Thailand currently has only 5 sites listed, so I picked 5 from the tentative list.