A fine example of Piedmontese neoclassicism, 18th-century Palazzo Boyl dominates Milis' manicured village centre. Originally a summer residence for the aristocratic Boyl family, it became something of a literary meeting place in the late 19th and early 20th centuries – Gabriele D’Annunzio, Grazia Deledda and Honoré de Balzac all spent time here. Nowadays it houses a small, rather neglected museum dedicated to traditional Sardinian costumes and jewellery. You'll need to call the town hall in advance to arrange a visit.
Opposite the palazzo, the 14th-century Chiesa di San Sebastiano features an impressive rose window in its Catalan Gothic facade.