Mysterious Devil's Bridge spans the lush Rheidol Valley where the Rivers Mynach and Rheidol tumble together in a narrow gorge. Just above the confluence, the Mynach drops 90m in a series of waterfalls. Devil's Bridge is itself a famous crossing point, where three bridges are stacked above each other. The lowest was built supposedly by the Knights Templar before 1188, the middle one in 1708 and the uppermost road-bridge in 1901.
It's one of many bridges associated with a legend that involves the devil building a bridge on the condition that he gets to keep the first living thing that crosses the bridge. An old lady then outwits the devil by throwing some food over, which her dog chases and everybody's happy – except the devil and, presumably, the dog.
Access to the waterfalls and old bridges is from beside the top-most bridge. There are two possible walks: one, just to view the three bridges, takes only 10 minutes (bring a £1 coin for the turnstile). The other, a half-hour walk, descends 100 steps (Jacob's Ladder), crosses the Mynach and ascends the other side. When the entrance isn't staffed (in winter and outside business hours) you can still enter through the turnstile by inserting two £1 coins.