What was a surprise to Americans and a shock?

One surprising and shocking event for Americans was the September 11, 2001 terrorist attacks. The scale and audacity of the attacks, which targeted iconic landmarks and resulted in significant loss of life, shattered the sense of security many Americans felt. This event prompted widespread changes in national security policies and had a profound impact on U.S. foreign and domestic affairs. The emotional and psychological effects of the attacks continue to resonate in American society.