Usually, by conflict - one King went out and bashed up his neighbours until his country was big enough to call itself an Empire. Sometimes, a marriage of royals and nobles from different countries could create an empire, if the couple inherited the thrones of both countries. (e.g. french Princess marries English Prince - Prince could become King of France and England). Rarely, a leader dying with no heir would leave his country to a foreign king. The latter two did not always create an Empire.
The first nation to build an empire was Southern Mesopotamia, a people known as the Sumerians.
Romans
Outlaw Empires - 2012 Crips 1-1 was released on: USA: 14 May 2012
The West African trade empires made their money mainly by trading slaves, salt and gold.
it was ghannas empire
Buddhism, Jainism
the group that built the empire is the Aztec.
there the ones who built their emir
One Incan achievement is that they built one of the largest empires in the Americas!
built a system of roadways throughout their empires
akkad
Both empires built powerful militaries with gunpowder weapons - Apex
Alexander the Great did not build one of the largest empires - he simply took over the Persian Empire and made it his own. Stealing, not building.
It changed because it was one of the first empires ever built in history. (:
The Portuguese and Spanish explorers and conquistadors built their New World empires by suppressing the Native Americans.
The main sources of wealth and power of all the West African empires was the armies they built whose superior iron weapons let them take control of the trade in salt and gold.
The great wall of china was not built at any one time, but was built by successive empires, then stopped, then built again. However, it is a good estimate to say it took over 500 years all together
I'm afraid not. There was not even a Rome in 4000 BC. You may be confused with the Egyptian or other Mideast empires.