Poolbeg Lighthouse

The Great South Wall was built between the 1710s and 1790s to stop Dublin Bay silting and to scour a channel into the port, and when it was finished it was among the longest sea walls in the world - about four kilometres of granite blocks laid without mortar, running straight out into the bay. Walking its top to the lighthouse at the end is a standard Dublin outing. The Poolbeg Lighthouse was first lit in 1768, rebuilt in stone in the early 1800s and painted red because it marks the port side of the channel entrance. From the wall the view covers the whole bay, Howth to the north, the Wicklow hills south, planes coming into the airport and ships passing close. It is completely exposed, the wall has no railing, waves break over it in rough weather, and the Poolbeg chimneys and a working port dominate the approach.

What you actually see

• The Great South Wall - four kilometres of unmortared granite from the 1700s.
• The red lighthouse - lit in 1768, marking the channel's port side.
• The bay view - Howth, the Wicklow hills and ships passing close.
• The industrial setting - the Poolbeg chimneys and a working port.

When to go

April to October for the walk in reasonable conditions. Avoid it in high wind or big seas - waves break clean over the wall. Sunrise and sunset are the reason many go.

Honest expectations

No railing at any point and the wall is slippery when wet. Waves overtop it in rough weather and people have been swept off. Four kilometres each way with no shelter. The approach passes an industrial estate and a wastewater plant.

Nearby

Sandymount Strand is south; the docklands and city centre are west.