Thanks to the efforts of historians and ethnographers, we know the history of most nations of the world. However, there are peoples whose history still holds many unsolved mysteries, writes russian7.ru.
Sumerians. Scientists failed to establish where these people came from and to what language family their language belonged. A large number of homonyms suggests that it was tone, and therefore the meaning of words depended on intonation. The Sumerians were one of the most advanced peoples of their time, they are the first in the Middle East began to use the wheel and created an irrigation system, invented a unique alphabet and Sumerian knowledge of mathematics and astronomy hits so far.