One of them, perhaps the wildest city in the history of the world, was established high in the Andes Mountains. The silver-mining city of Potosí, surrounded by nothing but snow and bare rock, ballooned to the size of London in the space of just a few decades. While fortune-seekers from Europe indulged themselves at the city's high-end brothels, thousands of indigenous people toiled and fought for their lives in the darkness of the world's largest silver mines.
Parián, the world's first Chinatown, hardly comes across as less bizarre. Located just outside Manila, Parián quickly grew more populous than the Spanish colonial city itself, as a labyrinth of shops, teahouses and restaurants grew up around a couple of large warehouses. Spanish agents came here to make their deals, and good silver from Potosí could buy almost anything, from leather boots to ivory chests to tea sets. Even skillfully carved marble figures of Jesus as a baby were on offer.
For China's rulers, though, this flood of silver proved a curse. The more of the precious metal Spanish galleons shipped to Manila, the more its value dropped. The result: inflation, tax deficits, bloody unrest and, ultimately, the collapse of the regime. The last Ming emperor was succeeded by the Qing Dynasty.
American Crops in China But even more than the silver itself, what played a key role in China's fate were three crops that arrived in the wake of the silver -- potatoes, sweet potatoes and corn. These hardy and unusually high-yield non-indigenous plants were able to grow even in soil that would not have supported rice cultivation.
These three American crops would transform entire swaths of land in the south and west of the Chinese empire, where the mountainous terrain had seemed unsuited to agriculture because the soil was either already depleted or too infertile to be farmed. The new plants from the Americas, though, transformed once barren land into arable land. With the Chinese government aggressively pushing agriculture, millions established a new livelihood as potato or corn farmers in the mountains.
Today, these imported crops from the Andes form a considerable part of the diet of China's billion-plus population. China is the world's second-largest producer of corn, after the US, and by far the largest producer of potatoes.
But this agricultural revolution had its downsides, as many mountain forests fell victim to the new cropland. These slopes, now cleared of trees, had no protection against the rain, and mudslides began to occur in many places. The areas around the Yangtze and Yellow rivers were now plagued nearly every year by massive flooding.
At China's central meteorological office in Beijing, Mann was able to examine maps that documented how the number and scale of floods changed over the course of the centuries. "Flipping thought the maps … was like watching an animated movie of environmental collapse," he recalls.
Changing Winners and Losers
Increasing contact between the continents certainly led to progress, but it brought suffering and exploitation, as well. There is almost nothing that people haven't had to sweat and die for, Mann writes, adding that his research taught him one thing above all: If we were forced to give up everything that was tainted with blood, we wouldn't have much left.