This medieval manuscript has provoked speculation since it turned up in a bookshop a century ago. Written in an unreadable script, it includes illustrations of plants, women and astrological symbols.
Known as the Voynich manuscript, it's named after Wilfrid Voynich, the collector and bookseller who acquired it in 1912.
The contents of the manuscript are widely believed to be related to medicine. Illustrations include these women, apparently bathing in pools of green liquid.