Here are three sentences describing a futuristic city:

Sentence 1: The city is a marvel of modern technology, with towering skyscrapers that seem to touch the clouds and streets paved with a glittering substance that makes the air feel like a thousand tiny stars.

Sentence 2: The city is a hub of innovation, with robots and artificial intelligence working alongside humans to create a utopia of efficiency and comfort.

Sentence 3: The city is a place of breathtaking beauty, with towering trees and flowers that seem to stretch up to the sky and a skyline that is a kaleidoscope of colors and patterns.

I hope this helps! Let me know if you have any questions or need further clarification.