Ancient China dreamed of future technology long before the modern age, conjuring visions of magic mirrors, ingenious machines and even lifelike wooden puppets.

In the Tang dynasty (618–907) text Duyang Miscellaneous Records, a mysterious stone called the “immortal mirror” appears as a precursor to the CT scan.

Found in the southwest of an unnamed land, the polished stone was said to span hundreds of kilometres.

Passers-by could look into it like a mirror, but instead of reflecting their faces, it revealed their internal organs.

The sick, so the story goes, could use it to locate the source of illness and seek the right herbal cure.

The Legacy of Kaiyuan and Tianbao describes a more portable version: an iron “illness-revealing mirror” small enough to carry.

A later Tang text, Yuanhua Ji, elaborates on the legend of an ancient mirror, a device with diagnostic and therapeutic powers.