Oh, and since the point of this thread was to add five more battles, here’s my list:
Mexico City (1847): Established the U.S. as the dominant power in the Western Hemisphere, fulfilled the Manifest Destiny, and sewed the seeds of imperial aspirations that would culminate in greater involvement in world affairs as the 19th century ended.
Antietam/Sharpsburg (1862): Essentially ended the Confederate State’s bid for foreign recognition. A lack of external support irreparably harmed the chances of a Southern victory.
Sedan (1870): It has been mentioned already, as it marks the ascension of Germany into imperial power status and begins her military aspirations that would culminate in two world wars.
Hiroshima (1945): No single discharge of a weapon has had so much impact upon the world. The dropping of a single bomb changed warfare and world politics forever. A 40-year Cold War and the threat of nuclear terrorist actions all stem from August 6, 1945.
Huai-Hai (1948): This is my sleeper. This was the battle that broke the back of Nationalist Chinese forces. Their losses along the Huai River and the Hai Railway prevented them from further contesting Communist forces for mainland China. In the 50 years since, the political and economic impact on the region has been more significant than almost all of the battles during the Pacific Theater of World War II.