I recently sat through a series of documentaries about world civilizations, and came across an interesting realization: Most of the maddest engineering projects undertaken worldwide have been for one singular purpose. That purpose being: Look what I can make, neener neener neener. They boast of a people being smarter and wealthier than the others.
But almost every civilization has had at least one mad project seen to completion. The French had Versailles and the Eiffel tower was quite insane for its time. German architecture was considered amazing in the middle ages. Even the Aztecs had a number of interesting projects, and many of my previous beliefs about them were proven wrong.
I had previously believed that the Aztecs had settled in their capital, what is now Mexico City, thousands of years before their demise in 1519. They had elaborate stone structures, and yet never discovered the wheel, which was a basic invention to most world civilizations. They also made a number of changes to the land around their swampy lake.
In fact, the Aztecs had been utterly nomadic before about 1200AD, and had built their grand city that so impressed the Spanish invaders in just 300 years, working out elaborate systems to make the swampy soil that they built on able to withstand the immense weight of such large structures.
I also assumed, since they were known to have elaborate porter systems, to have had their water delivered by runners carrying pots. They could not use the lake the built around, because the lake had brackish, undrinkable water. They did not have metal, so pipe wasn't available.
Instead, they independently invented the aqueduct, of a similar model to the one that kept Rome from getting thirsty. They knew enough about hydrology, stone cutting, and gravity, to keep a stone trench flowing all the way to their city. I did not know about this, since all of the structures that they built were totally destroyed in the invasion.
Foreign policy ultimately did the Aztecs in. When the Spanish arrived, every other tribe in the area sided with the Spanish against the Aztecs. Disease and superior technology damaged their civil and military abilities until they were forced to surrender, and their capital, Tenochtitlan, blasted to rubble. The Spanish drained the lake, built Mexico city over the ruins, and in their newly founded colony of Mexico, forced native people to dig gold for them until they revolted for independence hundreds of years later.