Murals are pieces of artwork painted or applied to walls or other permanent surfaces. These can be applied in paint, spray paint, using brushes, stencils, wheatpaste, mosaic, or many other mediums. They are often large and within viewable public spaces.
There is an overlap between publicly available murals and graffiti. Murals can be legally applied (created with the permission of the owner or municipality) or illegally applied. Generally, illegally applied murals are considered graffiti, whereas sponsored murals are portrayed or viewed as art. The terms "Street Art" and "Urban Expressionism" are often used synonymously with graffiti, and any of these can be used in the creation of murals.