From Wikipedia: http://en.wikipedia.org/wiki/Cape_of_Good_Hope

There is a misconception that the Cape of Good Hope is the southern tip of Africa, because it was once believed to be the dividing point between the Atlantic and Indian Oceans. In fact, the southernmost point is Cape Agulhas, about 150 kilometres (90 mi) to the east-southeast. The currents of the two oceans meet at the point where the warm-water Agulhas current meets the cold water Benguela current and turns back on itself—a point that fluctuates between Cape Agulhas and Cape Point (about 1.2 kilometres east of the Cape of Good Hope).