1) The Appalachian Mountains, running along the eastern coast of the United States, are one of the oldest mountain ranges in the world.

2) The Mongol Empire, under the leadership of Genghis Khan, became the largest contiguous empire in history, spanning from Asia to Europe.

3) The world's first paper money was created in China over 1,000 years ago.

4) The Berlin Conference in 1884-1885 divided Africa among European powers and set the stage for the colonization of the continent.