This may be found on Kildare Street and often hosts special exhibitions. Best of all it is free and worth visiting for the architecture alone.
Chances are that you will visit Trinity College Dublin and the Book of Kells. If you exit by the Arts Block gate/Douglas Hyde Gallery and turn right along Nassau Street towards the Tourist Information Centre, you'll pass an unobtrusive iron gate on your right. This is the entrance to the second St. Patrick's well. Unfortunately it is not open to the public and many Dubs pass it without a thought.
Surprisingly, many visitors never see Ireland's National Gallery on Merrion Street [see map section R-51]. There are many important exhibits by Irish and European artists and it's well worth a visit, least of all because it's free! There is also a good cafe.
While you're in the area, make a visit to nearby Merrion Square where you can see some excellent examples of the doors of Dublin. Many visitors will be familiar with them from illustrations, but few venture so far to see the elegant Georgian square with its beautiful town houses.