1) The fall of the Berlin Wall in 1989 symbolized the end of the Cold War and the reunification of East and West Germany.

2) The first commercial mobile phone, the Motorola DynaTAC 8000X, was released in 1983 and weighed nearly 2 pounds.

3) The Federal Reserve System, often referred to as the Fed, is the central banking system of the United States.

4) The Russian Revolution in 1917 resulted in the overthrow of the monarchy and the establishment of a communist government under Vladimir Lenin.