Civilization IV, how do you capture cities?

[Do Ya Like Popsicles?]

I do capture cities, but I don't know how I do it. Can someone explain for me?

 

[Oblivion Fan021]

just keep attacking the city till it has no more Defense

 

[Aleks]

You bring a lot of military units, you attack and capture. It is better to use siege weapons first to do some collateral damage and build your unit with Raider perk.