This 'Must See' must be interpreted literally: anyone walking/driving down the North Bull wall must see the needle at the end of the pier - you simply can't miss it!
This memorial was blessed on September 24th, 1972 by the arch bishop of Dublin and the memorial stone reads "To the glory of God and in honour of the most blessed Virgin Mary"
For all you curious VTers out there: "Realt na Mara" means "Star of the Sea". How appropriate!
Bus 130 leaves from Lower Abbey Street. In Clontarf (as soon as you see Dublin Bay, you're in Clontarf), get off at the 2nd stop after the stop at the Clontarf Bus Garage. The North Bull Wall (pier) is just across the street.
In the past there have been reports of perverts hiding in the dunes (and no, they were not just playing hide-and-seek...).
The police does come patrolling the island regularly, but just for your own sake, stay away from the dunes to avoid trouble.