Complex sentence: Other metropolises include Kraków, Wrocław, Poznań, Gdańsk and Szczecin--the country's largest urban agglomeration is the Silesian Metropolis.
Split into simpler sentences: Other metropolises include Kraków, Wrocław, Poznań, Gdańsk and Szczecin. The country's largest urban agglomeration is the Silesian Metropolis.