According to the Dublin Bus Tour, the Duke was not particularly fond of his Irish Heritage. The quote that they repeatedly use in reference is: being born in a stable does not make a man a horse. This is said to come from the Duke, however, it is misattributed and was made in a speech by Daniel O’Connell (1843) in reference to the Duke.
I mention all of this because the Ha’penny Bridge in Dublin was known for many years as the Wellington Bridge (the Iron Duke). In 1816, the cast-iron bridge replaced a ferry system that had fallen into disrepair and the ha’penny refers to the toll that people payed to cross.
The locks you see in one of the photos are Love Locks. Locks are affixed to a fence, gate, bridge by couples to symbolize their everlasting love.