"The Extreme 19th is the world's longest par 3, measuring 391 yards, and challengers can only access the tee by helicopter. Sat atop South Africa's Hanglip Mountain, at 400 metres tall it is also the globe's highest hole, meaning it takes almost 30 seconds for any tee shot to reach the Africa-shaped green below."
I suppose they added it as a 19th hole because no one would want the 10+ score it likely takes the average duffer to put one on from 560 yards up the mountainside . . .