Kazan metropolitan area is one of the largest metropolitan areas located in Russia which metropole includes the cities and districts of Tatarstan and Mari El republics: Cities: Kazan, Zelenodolsk, Volzhsk; Districts of Tatarstan: Atninsky, Verkhneuslonsky, Vysokogorsky, Zelenodolsky, Laishevsky, Pestrechinsky; Districts of Mari El: Volzhsky, Zvenigovsky. Wikipedia