Between 1914 and 1945 roughly 100 million Europeans died from political causes: war, genocide, purges, planned starvation, and all the rest. That would be an extraordinary number of deaths anywhere and any time. It was particularly striking in Europe, which had, over the course of the previous four hundred years, collectively conquered most of the world and reshaped the way humanity thought of itself.

The conquest of the world was accompanied by the transformation of everyday life. Music was once something that you could hear only if you were there in person. Literacy was useless for most of human history as books were rare and distant. The darkness was now subject to human will. Men lived twice as long as they had previously and women no longer died in childbirth as a matter of course. It is difficult to comprehend the degree to which, by 1914, Europe had transformed the very fabric of life, not only in Europe but in the rest of the world.

Imagine, in 1913, attending a concert in any European capital. Mozart and Beethoven would be on the program. It may be a cold winter night, but the hall is brilliantly lit and warm with women elegantly but lightly dressed. In that grand room, winter has been banished. One of the men has just sent a telegram to Tokyo, ordering silks to be shipped and arrive in Europe within a month. Another couple has traveled a hundred miles in three hours by train to attend the concert. In 1492, when Europe’s adventure began, none of this was possible.

There is no sound like Mozart and Beethoven played by a great European symphony orchestra. Mozart allows you to hear sounds not connected to this world. Beethoven connects each sound to a moment of life. Someone listening to Beethoven’s Ninth Symphony must think of revolution, republicanism, reason, and, truth be told, of man as God. The art of Europe, immanent and transcendent, the philosophy and the politics, all have taken humanity to a place it has not been before. To many, it seemed as if they were at the gates of heaven. I think, had I been alive then, I would have shared that feeling.

No one expected this moment to be the preface to hell. In the next thirtone years, Europe tore itself apart. The things that had made it great—technology, philosophy, politics—turned on the Europeans, or more precisely, the Europeans turned them on each other and themselves. By the end of the thirty-one years, Europe had become a graveyard of ruined cities, shattered lives. Its hold on the world was cracked. The “Ode to Joy” from Beethoven’s Ninth Symphony was no longer a celebration of European life, but an ironic mockery of its pretensions.

Europe is not unique in this. Other civilizations have undergone turmoil, war, and savagery. But the unexpectedness, the intensity, the rapidity, and the consequences for the entire world were distinctive. And most distinctive was that this particular civilization should be capable of self-immolation. There may have been hints of this in the cruelty of colonialism, the deep inequality of European society, and its fragmentation into many pieces. But still, the connection between European high culture and death camps is surprising at the very least.

The Europeans conquered the world while conducting an internal civil war throughout the centuries. The European empire was built  on a base of shifting sand. The real mystery is why European unity was so elusive. Europe’s geography makes unity difficult. Europe does not consist of a single, undifferentiated landmass. It has islands, peninsulas, and peninsulas on peninsulas—and mountains blocking the peninsulas. It has seas and straits, enormous mountains, deep valleys, and endless plains. Europe’s rivers don’t flow together into a single, uniting system as do America’s. They flow separately, dividing rather than uniting.

No continent is as small and fragmented as Europe. Only Australia is smaller, yet Europe today consists of fifty independent nations (including Turkey and the Caucasus, for reasons explained later). Crowded with nations, it is also crowded with people. Europe’s population density is 72.5 people per square kilometer. The European Union’s density is 112 people per square kilometer. Asia has 86 people per square kilometer. Europe is crowded and fragmented.

Europe’s  geography  means  it  can’t  be  united  through  conquest. It means that small nations survive for a very long time. The map of Europe in 1000 is similar to the map of 2000. Nations exist next to other nations for a long time, with long memories that make trust and forgiveness impossible. As a result, Europe has been a place where wars repeated themselves endlessly. The wars of the twentieth century were different only in that this time technology and ideology led to a continental catastrophe.

Europe is divided into borderlands, where nations, religions, and cultures meet and mix. There is frequently a political border within, but the borderland itself is wider and in many ways more significant. Consider the border between Mexico and the United States; it is a clear line. But Mexican influence, language, and people spread far north of the border, and likewise, American culture and business spread far south. In Mexico those who live in the states bordering the United States are seen as having absorbed American culture, making them alien to the rest of Mexico. Culture north of the borderland has transformed itself from Anglo to a strange mixture with a language of its own, Spanglish. The people living in these borderlands are unique, sometimes sharing more with each other than with those in their own countries.

I live south of Austin, Texas, where place-names are Anglo or German—the Germans settled the area west of Austin. When I drive south on I-35, towns tend to have German names like New Braunfels. As I get closer to San Antonio, they become Spanish, and sometimes I feel as though I am in Mexico. In a way I am, but the border is more than a hundred miles farther south, and that still has meaning.

Europe is filled with such borderlands, but the most important one divides the European peninsula from the European mainland, the West from Russia. It is a vast area that encompasses entire countries like Ukraine, Belarus, and Lithuania. Over the past century, we’ve seen the political border sweep far to the west, with Russia absorbing the borderland, or now far to the east, creating independent countries. No matter where the border may lie at any moment, this is a region whose people have more in common with each other than with Russia or the West. Indeed, the word Ukraine means “on the edge,” or borderland.

This is not the only borderland, although it defines European history. There is a borderland between the French and German worlds, stretching from the North Sea to the Alps. The Balkans are the borderland between Central Europe and Turkey. The Pyrenees are the borderland between the Iberians and the rest of Europe. There are even smaller ones surrounding Hungary, where Hungarians live under the rule of Romanian and Slovakian states. There is even a water border, so to speak—the English Channel, separating Britain from the Continent. In such a small area, crowded and filled with ancient grievances, there will always be borderlands, and no place demonstrates this more clearly than Europe.

Borderlands are where cultures mingle and where smuggling can be a respectable business, but it can also be the place where wars are fought. These are flashpoints. The Rhineland is now quiet, but that was not always the case. Since 1871, three wars have broken out in the area between the Rhine and the French-speaking regions. They were flashpoints then because there were deep and serious issues dividing France and Germany. And when the flashpoint sparked, the region caught fire. Today, the borderland west of Russia has become a flashpoint. It is igniting and fires have started, but, as yet, the tinder has not caught everywhere and there is no general conflagration.