The Thirty Years' War (1618-1648) was a continent-wide conflict that managed to ensnare every great European power of the time, initially with the Catholic Holy Roman Empire facing off against various Protestant states. A major turning point occurred in 1630, when Swedish armies led by King Gustavus Adolphus managed to turn the tide against the Imperial forces. After his death in the Battle of Lützen in 1632, the Protestant side faced serious setbacks against the Catholic armies of the Holy Roman Empire, and the end of the war with the Peace of Westphalia (1648) was largely based around settlements that were a setback from the heights of Sweden's power under Gustavus Adolphus.

The Battle of Waterloo, one of the most famous battles in history, was the final defeat of Napoleon Bonaparte by a joint British-Prussian force under the command of Generals Arthur Wellesley and Gebhard von Blucher. The campaign began when Napoleon returned from his initial exile on the Island of Elba in 1815. After Waterloo, Napoleon would again be exiled, but this time to the much more distant island of St. Helena and under much tighter security.

The Seven Years’ War (more commonly called the French-Indian War in American parlance) was fought from 1756 until 1763 between the French and British Empires. It was fought all over the world, as at this time the colonial possessions of Britain and France were nearly everywhere. The war ended with British victory and in America resulted in the complete loss of French possessions in Canada and the North of modern-day United States. This would have significant consequences, providing the motivation and circumstance for revolution. It also gave the British control of French holdings on the Indian subcontinent.

The fall of Constantinople occurred in the fifteenth century (1453), when Turkish forces finally overcame the last remnants of the Byzantine Empire and captured the city of Constantinople (now known as Istanbul). The Byzantine Empire was originally the Eastern half of the Roman Empire and the fact that it survived for an additional thousand years is somewhat remarkable. The fall of Constantinople precipitated the spread of Muslim settlements in the Balkans.

The War of the Roses was a civil war fought for control of the English crown between the Houses of York and Lancaster. The war lasted for thirty years and resulted in Henry Tudor, of House Lancaster, defeating his rival from the House of York, Richard III, and establishing the Tudor dynasty, which would rule England for over a century and included such notable monarchs as Henry VIII and Elizabeth I.

Napoleon’s Continental System is an important example of a blockade, or militaristic embargo, during times of war. Napoleon sought to cut off all trade to the British islands and prevent any territory under his control from exchanging goods with the British. The idea was to starve the British into surrender. The system had some effect, but it failed in part because other countries in Europe depended heavily on British imports.

The Reign of Terror began in 1793, when Maximillien Robespierre helped form the Committee of Public Safety and its associated Revolutionary Tribunal, which was empowered to try and execute the "enemies of the revolution." These enemies proved to be almost everyone not associated with Robespierre's Jacobin parties, leading to widespread anti-Jacobin sentiment among the masses. From the anger towards the Terror, the public wanted wholesale changes, which helped lead to the rise of Napoleon Bonaparte.

The assassination of Archduke Franz Ferdinand, heir to the Austro-Hungarian Empire, in Sarajevo on June 28, 1914 by Serbian nationalists was the immediate cause of World War I. How this conflict spread throughout the European continent was through a series of longstanding and complex alliances between various powers. When Austria-Hungary declared war on Serbia, Russia's alliance with Serbia meant it had to declare war on Austria-Hungary, followed by Germany declaring war on Russia, France declaring war on Germany, and then Britain declaring War on Germany.

During the early years of World War II, the Allies, and in particularly Britain, started to run low on supplies, but unfortunately most of Europe was under Nazi control and could not be counted on to trade. At this same time, the United States was attempting to remain neutral in the war, as many people were in favor of isolationism. Eventually the war became bad enough that it appeared as though the United States would have to pick sides, even without fighting directly. To avoid direct conflict, the Lend-Lease Act was passed in 1941, which allowed the government to give military supplies to foreign nations that were allies of the United States. This act made it so that the debts did not have to be paid back immediately, although typically the United States was given military bases in these countries in exchange for supplies. The act also essentially severed trade ties with members of the Axis Powers, as the U.S. began to help Britain, France, the Soviet Union, and other countries.

The trials of Nazi war criminals were conducted in Nuremberg, Germany due to the fact that the Palace of Justice located there was undamaged and provided enough space needed to detain the prisoners and hold trials. The trials started with the most significant war criminals in 1945, and those trials lasted almost a year. Of the most significant tried, twenty-four people were found guilty by an international tribunal. The rest of the trials were carried out from 1946 to 1949 by the U.S. military.