At Riviera Country Club, home of the Genesis Invitational, George C. Thomas designed a unique feature into the green of the par-3 sixth hole: a bunker in the middle of the green.
So why is there a bunker in the middle of the green of the 200-yard hole?
As it turns out, Thomas' odd feature creates what amounts to four different greens in one. By having the bunker in the middle of the green, Riviera's sixth hole has a putting surface divided into four quadrants. The best part about the quadrants is that all four are accessible for the player with the proper shot, and there are sideboards and backboards on all four quadrants which allow a player to shape the ball and use spin to reach the hole location. It's a brilliant design, really.
The bunker itself isn't all that large. It would almost qualify as a pot bunker. However, it's an obstacle when trying to go putt from quadrant to quadrant.
It also makes a somewhat convenient aiming point depending on where the pin is located in a given round. For a player that prefers to draw the ball, they'll want to use the bunker as a starting point to get to a pin on the left side. For a player that wants to cut the ball to a pin on the right side, they'll use the bunker as a guide as well.
Inevitably, some player will have to get their wedge out on the sixth hole and try to chip over the bunker in an effort to make the rare up-and-down for par from the green. That's completely legal under the Rules of Golf.
Over the years of the Genesis Invitational, there have been 14 holes-in-one on Riviera Country Club's sixth hole, with Dustin Johnson being the last to do it in 2010's second round.