Leinster House can be found between Kildare Street and Merrion Street – the former Dublin home of the Earls of Leinster is now the Irish parliament, both the Dail Eireann and the Seanad Eireann are based here. As this is the working parliament, access is by invitation (or election) only at most times. On Saturdays, guided tours may be available, however.
The building was erected in 1745 by Richard Cassels and is, in itself, not very exciting. The impact is further diminished by parliament's decision that it needed parking space more than landscaping.
For a view of parliament at work head for Kildare Street and hang around – this is the entrance the elected representatives use and you may spot some familiar faces (if you are familiar with the faces of Irish politics). There are also often citizens about venting their spleen or making a political point, expect some heckling if a minister of state arrives.
The best photo opportunity is, however, from the Merrion Street side – but only when the parking lot (one of Dublin's architectural crimes) is empty. Arrive early on a Sunday or bank holiday, at this time the light is ideal as well.