About 2,000 years ago, the powerful ancient kingdom of the Nabataeans hand-carved a city into the sandstone cliffs of Petra, Jordan. At its centre: an imposing, 12-column structure that has since become known as the Treasury.

Since then, archaeologists have attempted to understand what the structure was used for, with some speculating that it was a mausoleum built as the final resting place of an important ruler of this era.