Weatherman Derek Brockway sets off on some stunning walks around Wales. This time he heads to the hilltop 'Town of Giants' on the Llyn Peninsula and then discovers the most southerly point of Wales - the fascinating island of Flat Holm. Tre'r Ceiri is one of the most unusual and best-preserved Iron Age forts in Europe. It sits high above the old quarry village of Nant Gwrtheyrn, now best known as a residential centre for learning Welsh. Derek braves Flat Holm's colony of seagulls to discover more about the island's past, from the ripples of an ancient preserved seabed to Victorian gun placements. He also explores the ruins of Britain's only offshore cholera hospital. Show less