The Lost World and Mordor are about as 'out there' (or should that be 'in there') and surreal as any area of the quarry. These two great excavations sit above the even bigger hole of Twll Mawr and require complex approaches relying on ladders, tunnels and the odd abseil. Although the classics are few and far between, the routes that are worth climbing more than deserve the effort it takes to reach them.
Recent developments have also increased the appeal of the place with a set of good mid-grade sport routes being added to the upper section of The Lost World. This is also home to one of the stages of Snakes and Ladders.
Sadly the rock is not great and a number of routes have fallen down, often in a quite spectacular way. This particularly applies to the east side of both Mordor and The Lost World and any routes there should come with a bit of a health warning.