With bulging eyes, long, black braids, and an unnervingly large grin, Supay, lord of underground mines and other dark spaces, leers at visitors from his spot beside other art from Bolivia. Just downstairs, a geometrically patterned face sporting three horns adorned with monkey fur stares blankly across a room crowded with other Congolese artifacts. Steps away, an exquisite Torres Strait shark mask, made of tortoise shell, looks like it could come alive on its display stand. The British Museum has over 3,100 masks in its collection, of which only a…
