The Franco-Prussian War was a major victory for Prussia, which took less than 10 months from July 1870 to May 1871 to overrun the French armies and take possesion of the territories of Alsace and Lorraine. The war saw drastic changes for both countries. The French Second Empire was dissolved, with the Third Republic being established, and Emperor Napoleon III having to abdicate. The various German states were unified under a project long attempted by Prussian King Wilhelm I (who became German Emperor Wilhelm I) and Chancellor Otto Bismarck.

The Berlin Conference of 1884 to 1885 was set up to try and "peacefully" divide the territories of Africa between the various imperial European powers. This marked Germany's emergence onto the world stage as a significant imperial power.

During the Napoleonic Wars, Napoleon sought to isolate Britain from the rest of the world. In a process known as the Continental System, Napoleon prevented all the European nations under his control (which were most of them) from trading with Britain. The idea was that a British nation starved of much-needed imports and unable to raise revenue through exports would make for a much less challenging rival. In the end, Napoleon lacked the naval power to fully enforce the Continental System.

For much of European history what is now known as Germany had been a collection of numerous princely states and small kingdoms. Moreover, the German speaking people were scattered throughout Europe from the Netherlands and Denmark to Hungary and Romania. Now, whilst you may not have known that the unification of Germany took place in 1871, in the Nineteenth Century, you should have known that the Nineteenth Century was the century where European nationalism grew into a dominant political ideology. Different people all over Europe were suddenly coming to see themselves as part of a distinct, and usually “special”, nationality. Germany was no exception and under the chancellorship of Bismarck, Prussia used German nationalism to unify the country. You might also have been confused and considered the reunification of Germany at the end of the Cold War, when the Berlin Wall was taken down, but this would better be called the "reunification" of Germany. 

Neither Germany nor Italy were unified countries at the time of the Civil War so you can rule out this answer. Britain considered that a divided United States would be good for its economic interests, but because the British public would never support joining the Confederacy in a war that was seemingly about slavery the British government could not get involved. France likewise wanted the American union to break up because it had colonial ambitions in the continent still. Russia, however, under Tsar Alexander (the man who freed the serfs) supported the Union. It is highly likely that the most important factor that prevented France and Britain from getting involved was the fear that this would lead to another war with Russia.

The Battle of Lepanto was a naval battle fought in 1571 between the Ottoman Empire and the Holy League (an alliance of Venice, the Spanish forces of Charles V, and the Hapsburg forces of the Holy Roman Empire). The battle can be most clearly understood as a battle between Catholic and Islamic Empires for control of the Mediterranean. It was a significant victory for the Catholic forces. 

John Cabot was an Italian explorer who sailed for the New World in 1497 (just five years after Columbus' voyage) under the sponsorship of King Henry VII of England. He is generally considered to be the first European to set foot on the American mainland. Columbus, although widely credited with being the first European in the Americas, never made it past the Caribbean. It is also possible that Cabot may not be quite deserving of the credit bestowed upon him, as many historians consider it likely that the Vikings arrived in North America sometime in the eleventh century.

The Battle of Austerlitz is one of the most famous land battles of the Napoleonic Wars. The French forces of Napoleon defeated the combined armies of Austria and Russia and gave France control of most of the European continent. The Battle of Trafalgar is one of the most significant losses for Napoleon during his decade-long attempt to conquer Europe. It was a naval battle won by the British navy (led by Lord Admiral Nelson) that resulted in the annihilation of the French navy.

Albrecht von Wallenstein was a military commander from Bohemia who fought for the Holy Roman Emperor against the armies of Northern Protestantism during the Thirty Years' War. He was a highly succesful leader who won many battles, but his ambition and success began to worry the Emperor, who subsequently had him assassinated.

The Columbian Exchange describes the widespread exchange of animals, human populations, cultures, religions, diseases, and plants between the Old World of Europe, North Africa, and Asia and the New World of North and South America. It took place, primarily from the late fifteenth century through the seventeenth century and changed the very nature of the human experience.