The significance of the Berlin Wall in the 20th century lies in its symbolism of the Cold War and the division between East and West. Built in 1961, the wall physically and ideologically separated East Berlin, under communist control, from West Berlin, a democratic enclave. It became a potent symbol of the oppression faced by citizens living under communist regimes and the struggle for freedom. Its fall in 1989 marked a pivotal moment in history, heralding the end of the Cold War, the reunification of Germany, and the broader collapse of communist governments across Eastern Europe.