For more than a half-century, the whereabouts of one of the world’s most celebrated diamonds, the Wittelsbach blue, was obscure.

A major new exhibition of photographs from Bangladesh, Pakistan runs from Jan. 21 until Apr. 11 at the Whitechapel Gallery in London.

Photographer Juozas Cernius documents his visit to Robert Smithson’s monumental earth work, Spiral Jetty.