 Re: "I visited the place which is Korea."
Hello susan53,
In general your exlanations are pretty clear, but 1) either I do not understand everything or 2) they contradict what "A Practical English Grammar" (A.J.Tompson, A.V. Martinet) reads:
(p.19) "The definite article is used before a noun made definite by the addition of a phrase or clause: the girl in blue, the boy that I met, the man with the banner, the place where I met him. |