Ancient Mesopotamia's legacy was truly revolutionary. Childlike pictures scratched into wet clay evolved into the first written language. The Mesopotamians wrote the first epic poems, the first hymns, the first histories, and the first law codes. They developed the first wheel for transportation; simple carts that hauled bricks or produce morphed into chariots racing along at thirty-five miles per hour.

They gazed at the sky and mapped it, observing the planets' retrograde motions and predicting lunar and solar eclipses. They developed the concept of time, measurements, basic counting, higher math, and hydraulic engineering.

Mesopotamia gave birth to the world's first great empires-the Akkadians, Assyrians, Babylonians, and Achaemenids-which stretched over three continents.

A glimpse at the questions this overview unpacks includes:

• How old is the world's first city?
• How did the Eridu Genesis compare to Noah and the ark?
• How fast was the world's first postal system?
• How many times did Babylon's patron god Marduk get stolen?
• How did Hammurabi's law code compare to the Law of Moses?
• Who calculated pi (π) to the value of 3.125 and understood the Pythagorean theorem twelve centuries before Pythagoras was born?
• Did Xerxes really have a million men in his army?
• Which empire encompassed 44 percent of the world's population?
• What eunuch poisoned most of the Persian royal family?
• And much, much more!