Roman tombs and grottos decorated with fanciful murals of pastoral life gave rise to the word grotesque, but as the centuries passed, wall painting evolved into a fine art. Michelangelo's Sistine Chapel set the standard, and Monet, Matisse, Chagall, M!ro, Rothko and Delacroix all produced large-scale, immovable art works.
During Britain's 1980s economic depression, community artists in inner cities seized upon the mural as a cheap way to transform walls of derelict buildings into striking landmarks. But murals have always been an illustration of community spirit - and nowhere more so than in Northern Ireland.
Belfast's gable ends have become the gallery for a propaganda war waged by republicans and loyalists with paintbrushes. The outbreak of relative peace in the province has made these sectarian artworks a tourist attraction.
Just as political but far more accomplished are the many murals of Mexico City. In the 1920s and 1930s, three artists - Diego Rivera, David Siquieros and Jose Clemente Orozco - were commissioned to decorate dozens of public buildings (see Rivera's work from the National Palace, pictured above). Siquieros produced the largest mural in the world - the 50,000 square metre March of Humanity in Mexico City, and Rivera's fame led to a request to illustrate the foyer of the Rockefeller centre in New York. But Rivera was sacked and his mural destroyed after he attempted to portray Lenin as its central character.
In the developing world, murals are the media of advertising and propaganda. Large-scale likenesses of Iraqi leader Saddam Hussein adorn the streetcorners of Tehran, while in Afghanistan, Unicef's recent campaign to get children back to school was advertised by hastily painted murals on city walls.
But even as modern art becomes ever more conceptual, there are signs that the old fashioned mural is gaining a new respectability. Toby Paterson's 70-foot mural of Glasgow tower blocks won the prestigious Becks Futures award this year. And two pastoral scenes painted by homesick German prisoners on the walls of a prisoner-of-war camp in Harperley, Co Durham were declared a scheduled monument last month.
But as a cheap and cheerful celebration of local life, murals are easy to realise and hard to beat. Every town - and school - should have one.
Murals to visit:Ford Madox Brown's 12 panels in Manchester's Town Hall depict Victorian values. West Belfast's sectarian murals are centred around the Shankhill Road (loyalists) and Falls Road (republicans).Sandham Memorial Chapel, Burghclere, Hampshire (Sir Stanley Spencer's dramatic anti-war mural)