between 1839 and 1860 China and the Western world engaged in military clashes over what intoxicant?

In the early 19th century, Great Britain faced a significant trade imbalance with China. British consumers had a ravenous appetite for Chinese tea, silk, and porcelain, but the Chinese had little interest in British goods. To reverse the resulting outflow of silver, British merchants began illegally exporting a highly addictive narcotic grown in British India to China. This substance created widespread addiction and social devastation, turning the trade deficit decidedly in Britain's favor.

The Chinese government, led by the Qing Dynasty, repeatedly tried to halt the illegal trade. The situation came to a head in 1839 when a Chinese official, Lin Zexu, confiscated and destroyed over 20,000 chests of the drug from British warehouses in Canton. In response, Britain sent its technologically superior navy to protect its commercial interests, initiating the First Opium War.

This conflict, and a second one that followed from 1856 to 1860, are collectively known as the Opium Wars. China's defeat in these clashes resulted in treaties that forced the country to open its ports to foreign trade, cede Hong Kong to Britain, and ultimately legalize the very trade that had sparked the conflict. These wars marked a turning point, beginning a period of foreign intervention and influence in China that lasted for over a century.