Left Face B (also known as Mystery B) is a fantastic route up the front of Table Mountain which offers unparalleled views over the Cape Town City Bowl and Table Bay.
Getting there: drive up Tafelberg Road from Kloof Nek and park at the bottom of Platteklip Gorge.
Difficulty: pretty extreme exposure, a few short, uncomfortable scrambles, sections of difficult route-finding; you need to go with someone who has done the route before
Start out by heading up Platteklip Gorge. Cross the Contour path, and continue up Platteklip for about another 10 – 15 minutes. You will pass under a small but obvious band of rock before you reach the bend of the last big dog-leg on the zig-zags back into the Gorge, leave the path heading diagonally up to the left. This juncture is not easy to find and you need to look up the slope to the left to try and locate the cairn that marks the route.
The path resembles a rough water-course more than a trail at this stage as it heads up into the amphitheatre above you. As you enter the arms of the amphitheatre, start looking to head out to the right. The trail is more-or-less level for a while and you will have a chance to catch your breath.
Above you are the impressive and foreboding cliffs of the face of Table Mountain. It really looks like a summit from this approach is an impossibility; you must move around to the right, and climb some interesting little scrambles to reach a gully that cuts back up to the left.
At the top of this gully you will be out in the open again, and must continue hiking steeply up to the left until you reach the traverse that will take you across the face of the mountain. The traverse is wide enough to not be suicidal, but care must be taken as to your left is a huge drop. You will have to duck under an overhang at one stage.
The video below gives you a great idea of what the traverse is like.
The final assault on the summit is quite a challenge, and I must admit I had to take a break here even on my third trip up this route to gather myself and persuade myself that I was not about to lead the part like lemmings off the face of the mountain. There is a tricky little step over that requires all but the shortest must duck uncomfortably.
You will pop up on the summit of Table Mountain on the clear path that follows the edge of the front face of the mountain. From here, walk to the right to the upper cable station and you will find the top of Platteklip Gorge which is your route back down.
There is a great route description on Mountain Meanders.