[Editor’s Note: When Jacob Remes isn’t using his superpowers to fight crime, he toils as a PhD candidate in history at Duke University, where he’s writing a dissertation about the Salem Fire and the Halifax explosion. You can find more information here. And if you’d like to write a TDIH, please let me know.]

The workers at Korn Leather Company in Salem, Mass., made embossed patent leather by coating leather with a solution made of scrap celluloid film, alcohol, and amyl-acetate, and then applying steam heat. On this day in 1914, at about 1:30 in the afternoon, something went terribly wrong, and—perhaps not surprisingly given the flammable nature of the work—the whole rickety structure caught fire. Half an hour later, the fire had spread to fifteen more buildings, forcing 300 workers to flee. By 7:00 that evening, the fire crossed into the Point, a tightly packed neighborhood of three- and four-story tenements, filled with the immigrants who worked at Salem’s leather factories and the enormous Naumkeag Steam Cotton Company.

The Salem Evening News reported:

The rush of the flames through the Point district was the wildest of the conflagration, the flames leaping from house to house with incredible rapidity. Police officers and citizens went from house to house in the district when it was seen that it must fall a prey to the flames, warning the occupants to get out and get out as quickly as possible. Soon the streets were thronged with men, women and children, carrying in their arms all they could of their belongings, while wagons, push carts and now and then an automobile were pressed into service in the removal of goods.

The fire burned through the night, and by the time the fire reached the Naumkeag cotton mill, it was too hot; although the factory was equipped with modern devices to stop fires, it burned down, leaving 3,000 people without jobs. All told, the fire destroyed 3,150 houses and 50 factories and left 18,380 individuals homeless, jobless, or both. Of these people, nearly half were French-Canadian, the group that dominated the Point. “St. Joseph’s structure is not only destroyed, but the whole parish has been scattered to the winds,” the Salem Evening News wrote that week of the neighborhood’s French-Canadian parish. Many camped for weeks at nearby Forest River Park, under the watchful eye and armed authority of the National Guard.

Fires were endemic to 19th-century industrial cities. Just in the 35 years preceding the Salem Fire, Chicago (1871), Boston (1872), Seattle (1889), St. John’s, Nfld. (1892), Hull and Ottawa (1900), Jacksonville, Fla. (1901), Toronto (1904), Baltimore (1904), and San Francisco (1906), and Chelsea, Mass. (1908), among others, all suffered major conflagrations. But changes in building and firefighting meant that in the twentieth century, large-scale urban fires declined drastically. Automobiles required clear roadways, so the flammable material that used to often sit in streets, blocking fire engines and spreading fires, was gradually removed. Progressive building codes—like one proposed and rejected in Salem in 1910 that would have required noncombustible roofs—and ever-more professionalized fire-fighting helped too. If the Salem Fire was not the last of its kind, it was among the last. That at most six people died in Salem is testament to the strides made in preventing, containing and fighting fires, even when fire departments could not ultimately save property. In 1951, the National Fire Protection Association published a list of major conflagrations in the first half of the twentieth century. After 1914, only one urban fire came close to Salem’s in the number of buildings burned or the estimated dollar amount of damages: a fire in Astoria, Oregon, in 1922 that destroyed 30 city blocks and caused $10 million in damages.

Yet the decline of industrial conflagrations did not, of course, spell the end to urban disasters. Three and a half years after the Salem Fire, a ship explosion destroyed about a quarter of Halifax, N.S., killing around 2,000 people. The Halifax Explosion was an accident, but it heralded the urban destructions of the 20th century. All sides of the Second World War unleashed massive, unprecedented on cities. Geographer Ken Hewitt estimates that strategic bombing destroyed 39% of Germany’s total urban area and an astounding 50% of Japan’s. Neither these statistics nor the equally startling numbers of dead and bombed out (60,595 dead and 750,000 homeless in the U.K., 550,000 and 7,500,000, respectively in Germany, and 500,000 and 8,300,000 in Japan) adequately convey the destruction of families, communities, and institutions that came with these urban destructions. Twentieth century wars, their technology and ideology created a special brand of horror, which made their urban destructions starkly different from the industrial fires of the 19th century. When urban civilians became common targets, cities were made military symbols. It is not for nothing that terrorists have twice targeted the World Trade Center, a symbol of American urban might and culture.

If urban destruction in the 19th century was largely a result of industrial accidents and the destructions of the 20th century were from war, the 21st century may be a period of meteorological and seismological disasters. While there remains scientific disagreement about the effect of climate change on the frequency and intensity of hurricanes, there is mounting evidence that global warming has contributed to a greater proportion of storms being particularly bad. Global warming also contributes to other meteorological disasters, like floods, heat-waves, and droughts. Moreover, the chronic effects of global warming, especially coastal erosion, means that cities are less able to withstand extreme storms and floods. This means that cities will be more susceptible to destruction stemming from events that global warming will not increase, like tsunamis. There is some evidence, too, that even on land seismological disasters will likely become worse this century, since urbanization—especially the growth of shanties and slums in global megacities—leads to more death and destruction when earthquakes strike. As always, the social effects of these “natural” disasters are felt most by the poor, both globally and within developed countries.