Answer:
WWI and Kaiser Wilhelm II
Step-by-step explanation:
Beginning with Kaiser Wilhelm's ascension to the German Throne in June 1888, Wilhelm sought to rebuild Germany's image as a leading world power capable of challenging Britain and France. As seen in the German-Anglo Naval race and the French-German Moroccan disputes (Agadir Incident ), the new Kaiser sought to expand German influence on world stage. The problem however, with this aggressive bid to expand German influence, was that it heavily soured relations with the Great Powers of France and Britain. To top it off, Wilhelm disbanded the Reinsurance Treaty which helped maintain friendly German- Russian relations. Not only did the diplomatic move alienate the Russian, it deprived Germany of a crucial ally ( Russia was actually rapidly industrializing Pre WWI). Angered by Wilhelm, the Russians eventually moved to align with Germany's rival, the French, allying themselves with them. Eventually this alliance grew to include the British evolving into the Tripe Entente. This new political and military bloc was in direct opposition to Germany who had allies that were sorta trash (Austria Hungary and Ottomans). Beginning with WWI, Germany lacked strong allies and faced an enemy with superior resources and manpower. This pretty much ensured their defeat with led to their collapse. Besides the obvious economic strain of the war, the German Empire was in near collapse (lacking enough food due to British Blockades as well as raw materials). Eventually it did so, ending monarchist rule over Germany and the establishment of short lived democracy.
In Conclusion:
-Wilhelm's foreign policy helped intensify rivalries between his country and the top world powers (France and Britain)
-caused Germany to lose Russian support or at the very Russian neutrality
-deprived Germany of strong allies. Seriously the Ottomans and Austrians were absolute garbage and close to collapse (Even the Russians beat them easily).
WWI- destroyed the German economy and nation causing a massive strain. This caused the social unrest and massive protest eventually leading to collapse of the German empire and the beginning of the Weimar Republic.