The last event among the ones you listed is the Berlin Wall being built, which occurred on August 13, 1961.
Here’s a brief timeline of the events for context:
- The Korean War starts in 1950.
- The Warsaw Pact is formed in 1955.
- Germany is divided in 1949 with the establishment of East and West Germany.
- The Berlin Wall is built in 1961.
So, of these events, the Berlin Wall being built is the most recent one.