How to create a realistic city in Unity

For create a realistic city in Unity-

Start a New Project and call it Anything that you want.
Pay close attention to the folder you add your projects, as all files need to remain in the same location. Keep the default location for this project. Once your project is open, go to File > New Scene, and name your scene .

Now we start creating

create cube with scale y=0.01,x=1,y=15 and position it x=0,y=0,y=0 ad rename it as road.

create a cube x=10,z=10,y=10 and rename it to building.

Now, create street system and buildings by creating duplicates and scale them randomly.

Create a terrain with grassy texture and make and make sure it covers whole area of your city.

Your city will look like this-

Now, we need some texture search texture for road and building on Internet and download them.

Now drag and drop texture to your buildings to make them look real.

Add some trees to make it look more real.