Founded in 1592, Trinity College is the sole constituent college of the University of Dublin and the oldest university in Ireland. The campus covers about 40 acres right in the centre of the city — cobbled squares, green lawns, and buildings spanning three centuries of architecture.
The main draw for visitors is the Book of Kells, the lavishly illustrated ninth-century gospel manuscript displayed in the Old Library. Upstairs, the Long Room is just as impressive: a 65-metre barrel-vaulted hall lined with 200,000 of the library's oldest books and marble busts of scholars and writers. Timed-entry tickets sell out, so book online in advance.
Even without going inside, the campus is worth a wander. Parliament Square is handsome, the cricket pitch is improbably peaceful for central Dublin, and the Pav (the campus bar overlooking the pitch) is one of the best spots in the city on a sunny afternoon.