A mosaic artist starts by deciding on the picture, then chooses tiny cubes of coloured stone or glass called 'tesserae'. Each cube is placed by hand into wet plaster, one at a time, until the whole image appears. The best ancient mosaics needed teams of artists working for years to complete a single large floor.
The most celebrated mosaic in Hisham's Palace is called the Tree of Life. It shows a spreading tree with round fruits - some say pomegranates, some say oranges - and on one side a lion chases a deer among the branches, while on the other side deer graze peacefully. Scholars think it represents the balance of the natural world.
The palace was never fully finished - an earthquake struck the region before it was complete - but the mosaic floors survived underground for over a thousand years. They were uncovered by archaeologists in the 1930s and 1940s and are now carefully protected so that visitors can see them in the place where they were first laid.