From the Great Pyramid at Giza to the towering skyscrapers of today, humans have engineered massive constructions for at least 5,000 years. But why? How do biology and human emotions affect our desire to build gigantic structures? Why were the earliest mega-structures almost always pyramids? Why do people have the urge to build tall, and how do mega-structures on earth echo a basic principle embedded in the very structure of the universe?

Humans have small teeth and no claws or armor, so how do we project our power? Warfare has defined traditional history, but Big History digs deeper to reveal how it all began. We see how bat poop and ancient trees shaped the history of weapons, and link the gun all the way back to a change in our bodies that turned us into throwing machines.