Thalian Hall is a magnificent example of Italianate civic architecture and one of the finest 19th-century theatres in the American South. Built in 1858 to a design by John Trimble (a New York architect who had worked on several prominent theatres), it has a beautifully preserved interior — curved balconies, decorative plasterwork, and the intimate scale of a pre-microphone performance space.
The hall is still an active venue for concerts, theatrical performances, and film screenings. Tours of the building are available and worthwhile — a knowledgeable guide makes the history of the space comprehensible in a way that a self-guided visit cannot. The programming is ambitious for a city this size and tickets are affordable. If something is on the night you're in Wilmington, go.