Understanding Otto and the German Empire

During the documentary we heard a small section on former leaders who had influenced Germany, none of whom I had heard of; I realized that I don't really know a whole lot about German history in general. So, for tonight's research, I looked into German history through Otto von Bismarck.
Otto von Bismarck was born in 1815 and died in 1898. In his early career, he was sent as an ambassador to France where he worked for some eleven years. Through the Parisian lifestyle he gained new ideas on government, changing him from a conservative member of the elite to a slightly more liberal nobleman who acknowledged the importance and usefulness of a burgeoning middle class. In 1862, Bismarck was called back to Prussia where he was named Prime Minister by the conservative King William I. The king acted desperately, for he needed support in the expansion of the military to which the parliamentary houses were strongly opposed. Bismarck assisted his King in this case, later saying that "blood and iron" would resolve Prussia's future disputes. As it was, this was more of a liberal statement, showing that Bismarck intended the army for national unification and battle against an enemy, as opposed to the suppression of the German people. Nonetheless, Parliament officially rejected Otto in 1863, voting not to deal any longer with the chosen prime minister. Little did they know that his decisions in the next ten years would mark him as a national hero.
When trouble brewed in the duchies of Schleswig and Holstein between the Danes and the Germans, Bismarck allied Prussia with Austria in a war with Denmark. The pair won in 1865 and split the winnings - Prussia took Schleswig and Austria took Holstein. Otto then turned on his allies in 1866, marching the Prussian army on Austria. Within six weeks the Austrians were reduced to a secondary power within Germany. Prussia now had dominance. In the treaty to end continued conflict, Prussia annexed all cities that had participated in the effort to stop the Prussian troops.
These two wars had brought the separate states of Germany closer together, nationalism rising somewhat when the country was given a common goal. Bismarck attempted to use this advantage to bring all of Germany together under a single emperor and parliament. His endeavors to bring about unification failed, however, and he was left to think of how to further bring together the German people. A third war was in order. When, in 1869, the Spanish throne was offered to the king's cousin, he was given an opportunity to create one. Napoleon III took the Spanish offer badly, as an attempt to surround France and decrease its power. He sent an ambassador to kindly request that the king's cousin refuse the offer, an appeal that the latter agreed too. When the ambassador was sent a second time, asking that such an offer never be accepted in future, the king's cousin was not so cooperative. Bismarck took his chance, obtaining an account of the exchange and altering it slightly such that both Germany and France could take offense. The conversation was then made public. Furious at Germany's impudence, France declared war in 1870. A year later, the German Empire (including only as many states as could be allowed while maintaining an authoritarian government) was created. France was defeated and the new empire annexed the French provinces of Lorraine and Alsace, both of which were home to a considerable number of German speakers. Bismarck had achieved his prize of German unification, along with the added benefits of being the prime minister of Prussia and the first chancellor of the German empire.
The documentary stated that Otto von Bismark was the creator of a 20-year-long peace in Germany. Evidently, this referred only to the years following the creation of the German Empire by his hands.