Cyrn Las (The Grey Horn) or Diffwys Ddu (The Black Precipice) as it has been known in Welsh over the years, is a high mountain crag with a big feel. There are many classic routes, and none finer than Main Wall or The Grooves. All the routes are long and sustained with the harder ones having highly technical and demanding sections, such as Lubyanka and The Skull. This crag is steeper than Lliwedd and Cloggy and the climbing can be even more committing. Good mountain sense and route finding ability play a crucial role in helping you avoid becoming one of the many people who get off route on Main Wall.