The 2000s may have had war, terrorism, Bin Laden, and George Bush but it just can't measure down to the competition.
The 1860s had the American Civil War which, granted, was bad. Antietam (1862) was the single bloodiest battle in American history (23,000 dead), before or since. But the rest of the world was, by and large, doing fine.
Second Runner Up - 1910s
The Turks didn't invent genocide but they did practice it on a grand scale.The Armenian Genocide killed or exiled over a million people. Some 250,000 Assyrian Christians were slaughtered during the decade by Turks in present day Iraq and Syria. The Turks also killed three to four hundred thousand ethnic Greeks within the Ottoman Empire
Then there was famine and disease. The flu pandemic of 1918 alone killed 50 million people worldwide. Typhus and malaria killed millions more. By the end of the decade between 10% and 17% of able-bodied European men had died. Still, this was the lesser war.
First Runner Up - 1940s
|The wedding ring collection from the Buchenwald Concentration Camp|
As bad of this decade was it loses out on the Devil's prize because just about every evil was simply carried over from the previous decade.
The Decade From Hell - 1930's
Hitler rose to power in 1933 and before the end of the decade he would start World War II. The Nazis created their first concentration camp near Dachau just two months later. In 1935 the Nuremberg Race Laws were enacted. Kristallnacht came in 1938, Jews were fined for the damages done by the Nazi rioters.
The Spanish Civil War (1936-1939) was marked by the slaughter of thousands of innocents by the fascist general Francisco Franco. The Chinese Civil War between Nationalist and Communists had begun in 1927 but major combat didn't begin until the 1930s. It was postponed by the Japanese invasion of 1937. The Japanese atrocities in China (Rape of Nanking) were so ghastly the Nazis would have to work hard to exceed them.
Stalin in Russia was not fiddling during this decade. He used famine as a weapon of genocide in the Ukraine, killing some six million people slowly, by starvation.
In 1935, Mussolini began a colonial conquest of Ethiopia which by wars of the decade was minor but did include his use of poison gas while the Ethiopians castrated their Italian prisoners.
And in non-war disasters there was also the American Dust Bowl that blew "black blizzards" across the Plains states.
Special Prize - 1340s