miastem

In a sentence

• Kraków jest pięknym miastem.

  Kraków is a beautiful city.

  In this sentence, 'miastem' is the instrumental case of 'miasto' used with 'jest', expressing the quality of being a city.

• Zamieszkaliśmy w dużym mieście zwanym miastem kultury.

  We settled in a large city called the city of culture.

  Here, 'miastem' is used descriptively to attribute the characteristic of being a 'city of culture' through a complementary structure.

• Byłem kiedyś miastem otoczonym przez rzeki.

  I once was a city surrounded by rivers.

  This sentence employs 'miastem' in a figurative context, illustrating the instrumental case to symbolize a state of being or identity.