Disaster struck the world 100 years ago this week, leading to millions of deaths, wrecking cities, ripping old nations apart and creating new ones, overturning empires and the monarchs that led them, sweeping away traditional customs and values, and changing the world in ways that still affect us today.
On July 28, 1914, the Austro-Hungarian Empire declared war on the tiny nation of Serbia. Within a few days, the world's greatest powers were at each other's throats.
Thus began the Great War, or as we now remember it, World War I.
The centenary has been generating new books, news stories and analyses. But why should we care about something that happened a century ago?
Because in many ways, the world we live in is a product of World War I.
The world map as we know it basically was drawn in the war's aftermath. Now-familiar nations, like Iraq, were carved out following the war. Poland, which had vanished from maps in the 1700s, reappeared after the war. And much of recent news — sectarian violence in the Middle East, separatist fighting in Ukraine — can be traced to the breakups of the Russian Empire and the Turkish-based Ottoman empire caused by the war.
The conflict's most obvious product was human slaughter, raised to levels previously unimaginable.
From the war's beginning to its end, on Nov. 11, 1918, more than 13 million people were killed and 20 million were injured. About 7 million civilians died. No one knows the exact numbers.
The United States did not enter the fray until 1917, but still lost 320,000 killed or wounded — including more than 2,400 Kentuckians.
World War I ended forever the 19th-century vision of war as a glorious, manly adventure.
It produced numerous other changes as well.
The path toward eventual creation of modern Israel was cleared during World War I, when England formally declared itself in favor of a Jewish state in the area Palestinians also consider their homeland. Israel wasn't actually formed until after World War II — itself another Great War legacy.
Echoes of the war
The war's echoes are still discussed in classes at the University Kentucky's Patterson School of Diplomacy and International Commerce.
"You really can't understand how and why Israel became a state without understanding World War I," Patterson School Director Carey Cavanaugh said. "The collapse of empires that followed World War I really is what lays the foundation for everything that comes afterward in the Middle East."
Indeed, Cavanaugh contends that "the basic framework and pattern of international affairs today was set in place by World War I."
"The war still affects us," he said, "in more ways than most people realize."
In 1914, Europe hadn't seen a major war in almost 50 years. But tensions among the major powers were growing, along with ethnic unrest in many of the small countries they controlled. When the storm broke, it took common people and world leaders alike by surprise.
It went roughly like this:
Austria-Hungary, a multi-ethnic conglomeration of states in Central Europe, declared war on Serbia a month later. Germany, Russia and France declared war on each other a few days afterward, and England joined in.
Europe suddenly was split into two warring camps: England, France and Russia opposing Germany and Austria-Hungary, soon joined by their allies, Bulgaria and the Ottoman Empire.
Million-man armies were on a collision course by mid-August 1914.
"These tensions had been building since the 19th century, and 1914 was when they coalesced," said Karen Petrone, chair of the University of Kentucky Department of History. "But at the time, no one understood the kind of war they were getting into."
Petrone, who has extensively studied the war, is author of the book The Great War In Russian Memory .
"Everybody thought they would fight this nice little war, and be home in time for Christmas," she said. "Instead, they get this terrible war that is more massive, more destructive, more widespread and longer-lasting than anyone had imagined."
A clash of old and new
It was a conflict of strange contrasts, with modern weaponry meeting military tactics from horse-and-buggy days.
Cavalry still galloped into battle on horseback. Infantry traveled on foot; officers still carried swords.
French troops marched to war in traditional, brightly colored uniforms that made them easy targets for the deadly new weapons that modern technology provided.
Machine guns, recently perfected, mowed down soldiers in windrows. New cannons fired farther and faster than ever before. Airplanes, invented just 11 years earlier, became weapons for the first time. Poison gas and tanks soon followed.
The results were disastrous.
France lost 22,000 soldiers on one August day in 1914, suffering 329,000 casualties by late September. German and British losses were equally horrendous.
A bloody standoff soon developed, with the huge armies facing each other in trench lines stretching across Belgium and France. They remained there, periodically butchering each other in ineffectual attacks, for the next four years.
Yanks enter the war
The U.S. tried to stay neutral but gradually was pulled into the conflict as U.S. ships were damaged or sunk by Germany. The arrival of fresh American troops finally broke the battlefield stalemate, ending the war in 1918.
German leader Kaiser Wilhelm fled into exile and Germany's empire collapsed, as did the Austro-Hungarian and Ottoman empires.
Russia's empire already was gone, communists having seized control in 1917 to create the new Soviet Union. They also executed Nicholas II, the last Russian czar.
Poets and authors, many of whom had served in the trenches, produced waves of new works bemoaning the agonies of war. All Quiet On The Western Front by Erich Maria Remarque; Ernest Hemingway's A Farewell to Arms; and The Wasteland by T.S. Eliot became classics of 20th-century literature.
Other members of the "Lost Generation" tried to forget the war's pain by immersing themselves in the new freedoms of the Jazz Age and the Roaring '20s.
But the seeds for another, greater war had already been sowed. Economic chaos in Germany stemming from World War I opened the door for Adolf Hitler and Nazism to take control and put the United States on the road to war again in the 1940s.
"Without World War I, it seems doubtful there would have been a revolution that brought communists into control in Russia," Petrone said. "Without Germany's economic collapse in the 1920s, it's unlikely that the Nazis would have risen either."
What would the world have been like without Hitler? Without the Holocaust? If the Soviet Union had not been created, would there have been a Cold War? A Korean War? A Vietnam?
We can only guess.
Petrone says, however, that war in the early 20th century probably was inevitable.
"These issues of national identity were bubbling over," she said. "Had World War I not started the way it did, it probably would have started in a different way. It's hard to imagine how Europe could have avoided war for the long term."
When peace came, President Woodrow Wilson campaigned for a League of Nations to prevent future wars. But America, turning inward, refused to join it. The league proved too weak to prevent World War II.
Cavanaugh sees many of the problems that produced World War I continuing today, only in different form, in the Middle East, Ukraine and elsewhere.
"If World War I says anything, it is: Don't expect a lot of these problems to disappear easily," he said.
But, Cavanaugh points out, change is possible.
When fighting each other in World War I and World War II, France and Germany appeared to be permanent enemies.
"But if you drive between Germany and France today, you don't even have to slow down," Cavanaugh said. "There is total freedom of movement from one nation to the other.
"The old enmity is gone. Things really can change."