There is analyzed the new area of street art - graffiti. Mural art as an attribute of the modern street art is compared to its historical and cultural sources - earlier art forms (Paleolithic rock paintings, fresco of the Ancient Egypt, antiquity and Middle Ages, calligraphy). There are sorted out the metaphysical, conceptual, sacral, catharsis, aesthetic, scriptological, supportive, cultural and other functions of the mural art.