The answer to your question would be that the change that should be made to correct the sentence is the following one: Insert a colon after treasures. That is, the sentence would be as follows: We interviewed three experts on world treasures: an archeologist, a historian, and a museum director.
A colon means "that is to say" or "here's what I mean". You should use a colon to introduce an item or series of items. What is more, you should not capitalize the first item after the colon.