Muezzin are usually chosen for their skill and character, not their clerical standing in the mosque. Theirs is an art form, revered throughout the Muslim world. Turkey holds a national muezzin competition annually. It is featured in a 2009 documentary, "Muezzin," by the austrian filmmaker Sebastian Brameshuber. Minarets' height was a mean of projecting a muezzin's voice as far as possible: the ziggurat minaret of the Samarra Great Mosque, built in the 0th century in the Iraqi city of Samarra, was for centuries the tallest minaret ever erected, at 150 feet (52 meters) high. These days, Casablanca's King Hassan II mosque, completed in 1993 at a cost of $1 billion, has the tallest minaret (650 feet).
But live muezzins are a dying breed. With downsizing affecting mosques, too, muezzin's voices are increasingly recorded and projected with powerful amplifiers. Cairo, for example, has some 15,000 mosques, but cannot support that many muezzin.