Franco-Prussian War. Prussia initiated a war against France, who came and began to attack the southern german states. The southern states then ran for help to Prussia, who then advanced into France and gained the southern states into the North German Confederation. This was positive because it united all of the german states together.
http://www.timetoast.com/timelines/key-events-leading-to-the-german-unification
Primary Source 1. Napoleon dissolves the Holy Roman Empire and groups the German states into a new confederation, the Confederation of the Rhine. This united the Germanic people into one region and made them realize how similar they were through their cultures, languages, and common interests.
http://www.timetoast.com/timelines/key-events-leading-to-the-german-unification
An attempt to set up a unified Germany failed when the King of Prussia refused to accept the title of German Emperor. Most Germans preferred a loose confederation under the control of the traditionally strongest German power, Austria.
http://www.historyhome.co.uk/europe/unific.htm
This German dualism presented two solutions to the problem of unification: Kleindeutsche Loesung, lösung the Small germany (Solution germany Without), austria Or Grossdeutsche, großdeutsche loesung Lösung the (Greater germany Solution). germany with austria
https://en.wikipedia.org/wiki/Unification_of_Germany
The unification of Germany into a politically and administratively integrated nation state officially occurred on 18 January 1871 at the Versailles Palace in the Hall of Mirrors in France.
https://en.wikipedia.org/wiki/Unification_of_Germany
Historians have long debated Bismarck's role in the events leading up to the war. The traditional view, promulgated in large part by late 19th and early 20th century pro-Prussian historians, maintains that Bismarck's intent was always German unification.
https://en.wikipedia.org/wiki/Unification_of_Germany
Creation of the German Confederation under the presidency of Austria. Prussia and Austria were the two most powerful German states. Traditionally Austria was recognised as the most important.
http://www.historyhome.co.uk/europe/unific.htm
The southern states became officially incorporated into a unified Germany at the Treaty of Versailles of 1871 (signed 26 February 1871; later ratified in the Treaty of Frankfurt of 10 May 1871), which formally ended the war.
https://en.wikipedia.org/wiki/Unification_of_Germany
It was the beginings of a strong leader who would lead the German Confederation to unification through 'iron and blood'. Danish War and Seven Weeks' War. Prussia prevented Denmark from gaining Schleswig and captured Holstein from Austria.
http://www.timetoast.com/timelines/key-events-leading-to-the-german-unification
Under the hegemony of the French Empire (1804–1814), popular German nationalism thrived in the reorganized German states. Due in part to the shared experience, albeit under French dominance, various justifications emerged to identify Germany as a single state.
https://en.wikipedia.org/wiki/Unification_of_Germany
what events led to german unification
Danish War and Seven Weeks' War events led to German unification.  The events led to German unification  through 'iron and blood' and Danish War and Seven Weeks' War.