Iraq is known primarily for its rich maqam heritage which has been passed down orally by the masters of the maqam in an unbroken chain of transmission leading up to the present. The maqam al-Iraqi is considered to be the most noble and perfect form of maqam. Al-maqam al-Iraqi is the collection of sung poems written either in one of the sixteen meters of classical Arabic or in Iraqi dialect (Zuhayri). This form of art is recognised by UNESCO as "an intangible heritage of humanity".