Garter Lane Arts Centre is Waterford's main independent arts venue, presenting theatre, film, visual art, workshops, and local cultural events in the city centre. It is the sort of place that makes a historic city feel lived-in rather than preserved only for visitors.
For travellers, it is most useful in the evening or on a wet day, when a performance or exhibition can round out the Viking Triangle and crystal-factory circuit. Check the programme rather than treating it as a static attraction; the value is in what is happening there at the time.