In 1919 a steel storage tank burst in Boston and spilled 2.3 million gallons of molasses, creating a twenty-five-foot-high wave that killed twenty-one people and tore buildings from foundations. The tank had leaked since its installation, but the company had, in response to complaints, merely painted it a concealing brown.

Astrologers of the Ayyubid Empire predicted in 1186 that the world would end September 16 of that year; a dust storm, stirred up by planetary alignment, would scour the earth of life. Sultan Saladin criticized the “feeble minds” of believers and planned an open-air, candlelit party for that evening. “We never saw a night as calm as that,” an attendee later remarked.

According to sixth-century-bc Greek poet Hipponax of Colophon, in times of drought, famine, or plague an ugly or deformed person was chosen by the community to be pharmakós, or scapegoat. After being fed figs, barley cake, and cheese, he would be struck on the genitals with the bulbs and twigs of wild plants, led on a procession accompanied by flute, and burned on a pyre. His ashes were thrown into the sea. It is believed that Hipponax, whom Pliny the Elder once called “notoriously ugly,” may have been exaggerating the ritual.

Bibliophilic bishop Richard de Bury lamented the burning of the Library of Alexandria. “Who would not shudder at such a hapless holocaust, where ink is offered up instead of blood,” he wrote in 1344, “where the devouring flames consumed so many thousands of innocents?”

The opening of a particle accelerator at Brookhaven National Laboratory in 2000 inspired fears that high-speed collisions might launch a chain reaction that could turn the earth into a hyperdense sphere about one hundred meters across. A risk calculation determined this to be unlikely; if the collider were to run for ten years, the chance was no greater than 1 in 50 million. “The word unlikely, however many times it is repeated,” wrote concerned scientists, “just isn’t enough to assuage our fears of this total disaster.”