Which event marked a significant escalation in Cold War tensions in 1948?

The Berlin Blockade in 1948 was a pivotal event that significantly escalated tensions during the Cold War. Following World War II, Germany was divided into East and West, with the capital city of Berlin similarly split. In response to the introduction of a new currency in West Germany that the Soviet Union perceived as a threat to their control over East Germany, the Soviets initiated the blockade. This action aimed to cut off all ground access to West Berlin, effectively isolating it from the West.

The Western Allies, led by the United States and Britain, responded with the Berlin Airlift, a massive humanitarian effort to supply West Berlin with food and fuel through aerial means. This confrontation exemplified the deepening ideological divide between the capitalist West and the communist East and set a precedent for future conflicts. The blockade ultimately solidified the division of Germany and Berlin, which became symbols of the broader struggle between the two superpowers.

The other events mentioned, such as the establishment of NATO, the Korean War, and the Cuban Missile Crisis, occurred at different points in the Cold War timeline and were significant in their own right, but they did not occur in 1948 or mark the same level of immediate escalation as the Berlin Blockade did.