Not sure if this is a Mandela job or not.
For some reason, although I was good at geography as a child and loved looking at maps and atlases, I mixed up Cape Horn and the Horn of Africa.
I was astounded to discover via a TV documentary recently that the Horn of Africa is the big pointy bit on the right, not the general area at the bottom that leads to the pointy bit. That's Cape Horn, which is not actually, as I long believed, where the Atlantic and Indian Oceans meet.
They'll be telling me next that Cape Town is not stuck on the southernmost tip of Cape Horn. I'm going back to bed.