•Take in the dramatic architecture — and unexpected residents — of Dublin’s oldest building, dating back to 1864• Climb to the belfry and learn to ring the historic bells from a campanologist (or expert bell ringer)•Tap into Dublin’s cutting-edge art sceneMost visitors to Dublin take in the beautiful Christchurch Cathedral, Dublin’s oldest building, with its mosaic floor tiles, flying-buttress architecture, and soaring ceilings (if you’re lucky, the cathedral choir might be practicing when you’re there). But in-the-know visitors don’t leave without a visit to the cathedral’s crypt—the largest in the British Isles. That’s where you’ll find Tom and Jerry, the local nickname for a mummified cat and rat that were said to have got stuck in the organ pipes when chasing each other. (They even get name-checked by James Joyce in Finnegan’s Wake.) There are also a number of curious relics dating from the Christian Crusades, including a piece of wood from the crib of Jesus. Then climb the 84 stairs on the Belfry Tour and ask to ring the impressive bells, which weigh between a quarter and two-and-a-quarter tons, yourself. Now that you’ve seen Dublin’s oldest building, why not get a taste for the city’s more contemporary side? In the heart of buzzy Temple Bar, a five-minute walk from Christchurch, is the Project Arts Centre, where you can tap into the most cutting-edge art and performances in Dublin, including modern dance, comedy, high-energy interpretations of circus acts, and provocative video installations. Project also runs free lunchtime tours around Temple Bar’s top galleries; make sure to get the latest scoop on the coolest street art too. Christchurch Cathedral is on Christchurch Place, close to where Nicholas Street and High Street meet.  The Project Arts Centre is the large blue building on the corner of Essex Street East and Sycamore Street, near the banks of the River Liffey. CHRISTCHURCH CATHEDRAL: Christchurch Pl.; +353-(0)1-677-8099; christchurchcathedral.ie ​PROJECT ARTS CENTRE: 39 E. Essex St.; +353-(0)1-8819-613; projectartscentre.ie