Great place to visit and great views of north Wales. It's the perfect natural vantage point for a hill fort.
Originally the area below would had been marsh land, with streams and the original course of the river conwy, now the afon ganol (see pic from across the valley and imagine it full of water and marsh below).
Little is visible of the hill fort now, the top has a limestone outcrop running around it which can be mistaken for a wall or steps. A good view point to look at the hill fort is actually from the Colwyn Bay mountain zoo, you can clearly see the hill fort defensive walls from there.
The road beneath the hill is called Dinerth Road, this is a word that derives from the hill fort chieftan's (celtci tribe Deceangli) name 'the bear' and is also the name of the fort itself.
The Nant Semtpyr valley below (now the A55 runs along it- see second picture) is where (it is said and sometimes disputed) the romans were ambushed on their way to Angelsey, their leader Sepronious was said to be attacked there (Sepronious has connections with Hannibal).
In the Medieval times the hill was used as a rabbit warren. In WW2 it was used as an early warning signal outpost, a radio mast was fitted on top, signs of this are still visible. Behind the hill, from a small car park near a quarry, is the ruins of Llys Euryn with it's connections too Ednyfed who was the chief advisor to Prince Llewelyn ap Iorwerth and an ancestor to the Tudor King Henry 8th.