South Stack

South Stack is a small island just off the northwest coast of Anglesey, separated from the mainland by the Irish Sea. It is a sea stack made of sedimentary rocks shaped by centuries of wave erosion. The cliffs show folded layers of sandstone and shale, with thick beds of Holyhead Quartzite above them. These geological features have been recognised as one of the United Kingdom’s top 100 geosites. The folds are best seen from the steps leading down to the lighthouse. Similar rock formations appear in the cliffs to the south of the island. The lighthouse on South Stack was completed in 1809 and stands 41 metres above the sea. It has a 28-metre tower and covers seven acres, reached by over 400 stone and metal steps. Originally, visitors crossed on a basket suspended from a hemp cable. An iron suspension bridge replaced it in 1828, then a steel bridge in 1964, but the latter was closed in 1983. A new aluminium bridge allowed the lighthouse to reopen in 1997. It now attracts thousands of visitors each year. The cliffs form part of the South Stack Cliffs RSPB reserve, home to about 8,000 nesting birds during the breeding season. An RSPB visitor centre with a bird hide sits at Elin’s Tower on the mainland. From there, choughs, peregrine falcons and kestrels can be seen. The waters below hold harbour porpoises, grey seals, Risso’s dolphins and bottlenose dolphins. Part of the 200-kilometre Anglesey Coastal Path passes the site, while the Cybi Circular Walk offers routes around Holyhead Mountain.