Cader Idris (893m), or the 'Seat of Idris' (a legendary giant), is a hulking, menacing-looking mountain with an appropriate mythology attached. It's named in honour of a giant called Idris, a victorious Welsh prince of the 7th century called Idris, or both: the historical Idris may have been something of a giant.
It's also said that hounds of the underworld fly around its peaks, and that strange light effects are often sighted in the area. It's also said that anyone who spends the night on the summit will awaken either mad or a poet – although perhaps you'd have to be a little mad or romantic to attempt it in the first place. Regardless of its repute, it's popular with walkers and it's the park's favourite locale for rock climbers.