I didn't learn about the previous name Zaire from Wiki, learned about it from Ham Radio Dxing. Worked some stations when it was called Zaire. The last card I have with that name is 9Q5HX in Oct 97. Not sure when the name was officially changed, the card could have already been printed, and the operation was after the change. But regardless which name is on the card, if it's 9Q it's DR of The Congo. In my opinion, DXing is the best way to learn world geography. After working new countries and sending for the cards, I liked to look them up and learn more about them.
I was out one night dining with family. The waitress had an accent that sounded African, and I asked her nationality. She said she was from Liberia. My sister told her that her English was so good. I smiled and said, "English is the official language in Liberia." My sister's husband, who is a retired high ranking Air Force officer and former cargo pilot, asked the waitress if she knew about Zaire. He said he had been there a couple of times. The waitress said she didn't know about that country. I smiled again and said, "Zaire doesn't exist anymore." He looked at me like he was thinking, "WHAT." Then I told him about the new name. So case in point, Ham Radio Dxing is the best geography teacher there is.
BTW: There's two Christmas Islands. (two that I know of) One is on the DXCC list as VK9, and the other is part of Eastern Kiribati (T32) and good for IOTA. (OC-024)