Coliemore Tightmore, Dalkey, Co Dublin
Coliemore harbour used to be the main harbour for all of Dublin as it was sheltered by the island and had a very deep channel between it and Dalkey Island. 
 
Hard to believe and one of the reasons that all the castles were built in Dalkey to safely store all the goods arriving from abroad.
 
Now it's just a quaint little fishing harbour and some of the local lads suspend their slackline across it as can be seen in this photo.