There are 4 holes that could be deemed fortress holes at Olympia Fields, each different.
The best may well be no. 6 on the South Course. Only 360 yards or so, it allows both the best and the rest of us to make 3 or 13. The green is about 20 feet higher than the fairway, and has 10-15 foot falloffs in front and to the left, which can be seen from the fairway, but a very steep 20-25 foot falloff into the "kitchen" on the right. The hole is being restored closer to its original configuration so that you will be able to play safe to the left, and have the green at an angle and playing right toward the kitchen, or you can firt with bunkers on the right and be shooting straight up the long, narrow, very sloped green.
No. 12 South is 210 yards par-3, again to a very sloped green perched up 20 feet above a fairway mown area. Go past the pin and there is a real chance of putting off and down the hill. If your tee shot ends up at the bottom you have a real chance to use the "automatic ball retrieval system" which sends any ball not hit hard enough back to your feet.
No 3 on the North is 450 yards (or more from the back), with a tee shot and an upper fairway that goes about 175 yards, and then a steep drop to a blind lower fairway. Butterfield Creek crosses the fairway about 100 yards from the green. The green is fairly visible, but stands starkly out, with a bunker left and stair-step bunkers right. Really fun tee shot looking at nothing but a far away tree line, and vary challenging approach for better players. The rest of us often layup in front of the creek, and have a really fun wedge, with the ball standing out against the sky, and waiting to see whether there will be a chance at par.
14 North is also a form of fortress, 440 yards, and the most beautiful, with the creek crossing the fairway just past the tee, going up the right side of the fairway, and crossing again 150 yards from the green. The green is basically blind on the approach, and there is an abrupt elevation change at the far creek bank - you're looking at a 10 foot soil "wall" on the approach, to a green 20-30 feet above you that slopes severely from back right to front left. You can easily putt off the green if you go past the pin, and the ball can roll 10-20 yards down. Neither 3 nor 14 have any fairway bunkers - they don't need them.
All four are natural holes, and, except for 12 South, which was changed in 1921, a testament to the routing abilities of Willie Park Jr. on the North, and Bendelow on the South (hey, he found 6). I find 6 South superior, only because anyone can make 3 or 13 there, while regular players have little chance on the other 3.
Jeff Goldman