Thespian Hall is the unassuming Greek Revival temple that dominates the corner of Main and Vine, with four squat brick columns and a low pediment. Built in 1855 by a citizens' theatrical society, it claims to be the oldest continuously used theatre west of the Allegheny Mountains — a title it backs up by hosting performances every season since the 1870s.
The interior was restored in the 1980s and is small, intimate, and acoustically excellent. It hosts the annual Missouri River Festival of the Arts each summer (chamber music, dance, opera) and a year-round programme of plays and concerts. Daytime visitors can usually walk in for a quick look at the foyer and auditorium when the building is unlocked.