Mungo Park, a young Scottish surgeon, set out in 1795 to find the Niger River in West Africa, which Europeans had heard of but never reached in its central stretch. Backed by the African Association and Sir Joseph Banks, he travelled up the Gambia, learned the Mandinka language and spent two years on the journey, including four months held prisoner by a Moorish chief and months nursed by a stranger when he was ill. He reached the Niger, saw it flow eastward, and returned to Scotland in December 1797, long thought dead. His 1799 book, Travels in the Interior Districts of Africa, was a best-seller. On a second expedition in 1805 he went far down the Niger but drowned in its rapids.

In 1909 D. W. Griffith made a 14-minute film about a speculator who corners the wheat market and doubles the price of bread. A farmer sows his field while a 'Wheat King' gambles in the Chicago wheat pit; bakers raise the loaf from five cents to ten and the poor line up for bread. Griffith cut back and forth between the farm, the feast and the breadline, a technique called parallel editing, so audiences saw both ends of the economy at once. The film drew on Frank Norris's stories and on a real scheme: months earlier Chicago financier James Patten had cornered wheat, sent bread prices up and made about $5 million, roughly $185 million today.