Guano, rich in nitrogen and phosphates, met a European and American need for fertilizer once chemists explained soil depletion. Peru's state monopoly and British trade turned it into a vast export.
Starter thread · AI-reviewed against its sources
The Columbian Exchange was the transfer of plants, animals, diseases and people between the Americas and Afro-Eurasia after 1492, reshaping diets, populations and ecosystems on both sides.
Starter thread · AI-reviewed against its sources
The Silk Road was a web of land and sea routes, not one road. Goods, technologies, religions and ideas moved in stages through many hands, and silk was only one item.
Starter thread · AI-reviewed against its sources
The potato raised Europe's food supply, curbed routine famine and fed population and city growth, though historians disagree on whether elites or peasants drove its spread.
Starter thread · AI-reviewed against its sources
Sailors compared local time with the time at a fixed point such as Greenwich. They got Greenwich time from a marine chronometer or from the Moon's position, a method called lunar distances.
Starter thread · AI-reviewed against its sources
Tea created a silver drain from Britain to China. Britain countered by smuggling Indian opium into China, and the clash over that trade led to war in 1839.
Starter thread · AI-reviewed against its sources
Salt was essential, widely needed and easy to control, so states taxed it, monopolized it and built trade routes around it, from ancient China and Rome to Venice and British India.
Starter thread · AI-reviewed against its sources
