As a proportion of the population, more people were killed during the An Lushan rebellion in eighth-century China, for example, or by the Thirty Years War in 17th-century central Europe.

ECONOMIST: The second world war

And yet during the period of the Thirty Years War (1618-1648) Elizabeth was one of the foremost power brokers for the Protestant cause in Europe.

BBC: A Point of View: The Winter Queen of Bohemia

After Gertrude's death, the dynasty she had put in place continued for thirty-two more years, while Europe plunged into war again after only thirteen, dragging the rest of the world with it.

NPR: Excerpt: 'Gertrude Bell'

Yet a mere thirty years after the end of the Franco-Prussian War, when the smallpox epidemic swept through the United States, a whole host of intelligent people refused to be vaccinated, convinced that the vaccine did more harm than good.

FORBES: When Americans Rejected Small Pox Vaccines