An amazing feat of engineering, and unique in Europe, the cliff railway at the Centre for Alternative Technology is an ecologically sound way of transporting visitors between the car park, which is at valley floor level, and the centre itself which is in an old slate quarry, 180ft above. There are two carriages which are linked by a steel rope. A tank in the carriage at the top is filled with water until its weight is sufficient to pull the other carriage and its passengers up the 35 degree incline. A lake, filled by a spring in the quarry and also home to various wildfowl and fish, is used to provide the water used by the cliff railway.