Curious, unexpected and a bit mysterious are words that could describe an iconic science fiction series – or some of Sotheby's most memorable lots. In the spirit of The X-Files revival, set to premiere this Sunday, we explored our archives for artefacts and objects so unusual and rare they need to be seen to be believed.

LAUNCH SLIDESHOW

SKULL, CENTRAL AMERICA OR EUROPE, 19TH/20TH CENTURY. SOLD FOR $5,808.