Murals are the earliest known forms of non-sculptural art. The 19,000-year-old cave paintings in Lascaux, France, and elsewhere in Europe are murals; they required nothing other than handmade paints, usually made from iron oxide and coal ash, and brushes. The first mosaics, which depict battles, appeared during the Mesopotamian Empire, around 4000 B.C.
As its etymology implies ("mur" is "wall" in Latin), murals can be created on any flat surface; one of the world's tallest existing murals, in Abu Dhabi, United Arab Emirates, runs along the elevator shaft of a high-rise hotel. Conversely, because of the amount of intricate inlay work required to create a mosaic, they tend to be smaller than murals. Modern mosaics, however, can be created to large scale via computer imaging techniques.
Murals usually are paint based; they can be painted directly onto a wall or else onto mounted canvas. Because of their exposure to the elements, mural artists often use long-lasting, acrylic-based paints. Mosaics are made of tiny chips of stone and other physical objects, called "tesserae." Tesserae must be glued individually to the wall or floor where the mosaic is being produced.
Advertising murals began appearing on walls at the end of the 19th century. During the Depression, unemployed workers were commissioned to create outdoor murals in public areas. Since the 1960s, community murals have been a source of both empowerment and beautification in low-income areas. While modern mosaics can, and do, have social and political significance, their comparatively higher creation cost makes them rarer.