America's emergence as an active, operational world-power did not occur until the 1940s. During World War II and then beyond, America's industrial, military, and other capacities were finally evident as the strongest in the world. It was World War II which both marked and to a large extent caused this phenomenon.
The conclusion of the Cold War was marked by the dissolution of the Soviet Union in 1991. This event effectively ended the ideological and geopolitical struggle between the United States and the Soviet Union that had defined the post-World War II era. The fall of the Berlin Wall in 1989 and the subsequent reunification of Germany also symbolized the end of the Cold War. The conclusion of this conflict led to a significant shift in global power dynamics and the emergence of the United States as the world's sole superpower.
A couple of events come to mind, part of the winning side in WW1 and WW2
Hernán Cortés defeated the Aztec Empire, led by Emperor Moctezuma II, during the Spanish conquest of Mexico in the early 16th century. Cortés and his forces captured the Aztec capital, Tenochtitlán, in 1521, which marked a significant turning point in the Spanish colonization of the Americas. The conquest resulted in the decline of Aztec power and the establishment of Spanish rule in the region.
The first atomic power station in the world is the Obninsk Nuclear Power Plant, located near Obninsk, Russia. It was commissioned on June 27, 1954, and had a capacity of 5 megawatts. This plant marked a significant milestone in the development of nuclear energy for electricity generation.
World War I is significant because it marked the debut of many new types of weapons and was the first huge war to benefit from technological advances in radio, electrical power, and other technologies
Supreme commander in chief of allies
The Spanish American War.
Emergence of monopoly power and concentration
The conquest of Constantinople
No single event marked Rome as the dominant power in the Mediterranean. It was more of a process than an event, one which involved victories in wars. One was the Pyrrrhic War. The First and Second Punic Wars established Rome's dominance in the western Mediterranean. The Roman-Syrian War and the Third and Fourth Macedonian Wars made Rome the great power in the eastern Mediterranean and the Third Mithridatic War ended challenges to her power and led to her dominance over Turkey and the Levant.
Both Britain and France challenged Spanish power in the Americas.
The President of India.
how did the panama canal increase americas power in the world
The Berlin Conference of 1884-85 regulated European colonization and trade in Africa during the New Imperialism period, and coincided with Germany's sudden emergence as an imperial power.
When the Tang Dynasty finally rose to power as a ruling empire.
great britains emergence as a major naval power
Britain lost to the American colonies during the American Revolutionary War, which lasted from 1775 to 1783. The conflict culminated in the signing of the Treaty of Paris in 1783, recognizing the independence of the United States. This marked a significant shift in power and the emergence of the U.S. as a new nation.