What are the bar below cities' name in cultural advisor (civ vanilla)

[Milan's Warrior]

I have vanilla.

In the cultural advisor screen, there is a bar just below the city name.
What does that bar indicate?

 

[Aggie]

It tells you how long you have to go until the next border expansion.

 

[Frollo]

It tells you how long you have to go until the next border expansion.

That's right.
And I want to add that in the city screen for each city, you can see the same bar, somwhere near the upper right corner.

 

[Milan's Warrior]

oh, thanks.