Final answer:
The Greeks and Romans painted large frescoes on walls, not canvases. Frescoes are paintings created by applying pigments on wet wall plaster, resulting in a permanent part of the plaster wall.
Step-by-step explanation:
The Greeks and Romans painted large frescoes (also known as murals) on walls, not canvases. Frescoes are paintings created by applying pigments on wet wall plaster, resulting in a permanent part of the plaster wall.