“There is just one civilization in the world.”
The world seems to be divided. For example, we have cultural or religious differences. There is the European civilization. There is the Islamic civilization. However, our civilization is what we make of it. Civilizations are not different because people have different genes, or there are hard religion beliefs that define what it is. Civilizations are different because we define them in a different way. The differences are only in our minds, and physically there is no significant difference.
All countries agree on all the basic stuff. Each country has a similar flag, an anthem that is in the style and composition of Beethoven, and so on. Each country might have a different government, different laws, but they all agree for the most part on the fundamental elements of our one global civilization.
And at the end of the day, all human civilizations are slowly merging with each other into one.