Opened in 1956 as the King George VI Art Gallery, this is a small but properly curated museum with a strong collection of South African art across periods — colonial-era landscapes, apartheid-era political work, and contemporary pieces by Eastern Cape artists. The building itself, a solid 1950s civic structure on St George's Park, is handsome without being grand.
The collection is strongest on Eastern Cape and Karoo subjects, which makes it more interesting than it might sound: the landscape of the region has attracted painters for two centuries, and you can trace the changing way the land and its people have been depicted from the 1800s to now. Admission is free. It is a good place to duck into on a hot afternoon and spend an unplanned hour — it's modest enough that you won't feel you're shortchanging it by not staying longer.