Final answer:
The most memorable change of the twentieth century was the extensive advancement in technology and its role in globalization, encompassing shifts in power after world wars, scientific breakthroughs, and cultural revolutions.
Step-by-step explanation:
The twentieth century was a period of unprecedented change, marked by major transformations in nearly every aspect of life. In my opinion, the change that should be remembered most about the twentieth century is the vast advancement in technology and its impact on globalization.
The century began with the dominance of certain European countries, but as technology progressed, power dynamics shifted, leading to a world more interconnected through advancements in communication, transportation, and industrial technologies.
Two world wars changed the geopolitical landscape, and the rise and fall of the Soviet Union during the Cold War drastically realigned global power structures.
Meanwhile, science and culture underwent their own revolutions, with medical breakthroughs extending human lifespans and modernist movements reshaping art and literature. The profound effects of these changes are still felt in the 21st century, making them undeniably significant historical landmarks.