The National Museum of Rome has an entire room set up with frescoed walls. (Frescos were created by laying down a fresh coat of plaster and then painting it before it dried. If you made a mistake, you had to take all the plaster off and start over.)

This is one small section of the walls, which depicted an entire garden. It must have been gorgeous when the colors were fresh and there was natural sunlight pouring in. (The museum has to keep it in near darkness in order to preserve it. Fortunately, digital cameras are very good in low light.)