Running and securing an empire can get expensive–especially one known for its opulence, like the Mughal Empire, which conquered much of northern India before rapidly declining in the 18th century. But how did the Mughals get their money? Often, it was through wealthy merchants, like the Jhaveri family, who willingly—and then not-so-willingly–funded the empire’s activities.

For two centuries, the Xiongnu people—a vast nomadic empire that covered modern-day Siberia, Inner Mongolia, Gansu and Xinjiang—were one of the Han Dynasty’s fiercest rivals. They raided the wealthy and prosperous Chinese, and even forced the Han to treat them as equals—much to the chagrin of those in the imperial court.

China’s rise to global prominence is a pretty good contender for the most important world development in the past 30 years. But now the question is how Beijing managed to be successful on the international stage, let alone how large that success is—with fierce debates between hawks and doves in the West and elsewhere.

In April 1942, at least half a million people fled the city of Madras, now known as Chennai. The reason? The British, after weeks of growing unease about the possibility of a Japanese invasion, finally recommended that people leave the city. In the tense, uncertain atmosphere of 1942, many people took that advice to heart—and fled.