There are 224 countries and regions in the world, including 193 countries, 3 1 regions and more than 2,000 nationalities. The total number of ethnic groups in Asia exceeds 1000, accounting for about half of the total number of ethnic groups in the world, and it is the continent with the most ethnic groups. There are about 170 ethnic groups in Europe, and there are about 20 single-ethnic countries. If the history is the oldest, it should be the Han nationality, which began to form a unified Chinese nation about 5,000 years ago. Although there were ancient nationalities in other places in ancient times, most of them disappeared with the passage of time. For example, today's Jews, whose predecessors were Hebrews, used to be the northwest branch of Semitic people. It cannot be said that the history of Jews can be traced back to 2400 BC, because the existence of a nation is definitely the same.