Meet the new feature: Religion
Religion is one of the things that are totally new for Civilization and for strategy games in general. With the discovery of certain technologies new religions are also born. For example, Theology and Meditation give Christianity and Buddism. If you are the first to discover this advance, one of your cities converts to the new religion and becomes a Holy City. After that this religion starts spreading all over the world. To make this passive process quicker you can build missionaries and send them to other nations in the hope they will convert too. Also, religion allows you to build temples and monasteries. Every city that chose a religion brings money to the nation controlling its Holy City.
One of the available religions can be picked as State Religion. This gives you 1 happy citizen to every city that has this religion. State religion also influences the relations with rival civilization (those with the same religion tend to like you more and may choose to be less aggressive). In addition, depending on currently chosen civic options State Religion can have a great impact on the level of happiness in you empire (kind of religion tolerance). Born Great Prophets can build shrine of the religion - a World Wonder that helps the religion to spread faster.
копии швейцарских часов