King John's Castle. It was unfortunately closed to the public the day we visited but we were able to visit the museum, which was a fascinating look into the history of Limerick and the castle.
Thomond Bridge and Saint Munchin's Church
I have come to the conclusion that even the blackest of thumbs can grow flowers in Ireland. Everywhere you look there are flowers cascading over window boxes and pots in a seemingly endless display of color. It's almost a Ronco "set it and forget it" feel to horticulture. Just enough rain and sunlight keeps it blooming all summer long.