The hill of Pen Dinas and is the site of an Iron Age hill fort. Close by there is also a Bronze Age burial mound on the southern summit. There were originally two forts here that were then joined together making it an extensive site. The first of the forts to be built was on the northern lower summit and then a further one was built on higher ground to the south. The site is on the coast just south of the town of Aberystwyth.