On August 20, 1968, massive military forces of the soviet Union and four other Warsaw Pact States occupied Czechoslovakia suddenly and without warning for fear that the reform would contaminate other Eastern Europe Countries.

• 为了防止捷克斯洛伐克的改革蔓延到整个苏东地区，1968年8月20日，以苏联为首的华约五国悍然入侵捷克斯洛伐克，从而打断了“布拉格之春”的改革进程。 这一事件震惊了整个世界。