Nations around the world prepare for the anticipated effects of the Y2K (year 2000) computer problem — the need for computers and computer-dependent activities to switch to recognize the change to a new century. The key role of computers in society leads to predictions of widespread communications, banking and transportation breakdowns. The United Nations establishes an Internet Worldwide Y2K Watch to coordinate reports from more than 170 countries about Y2K events. Also that year:

• Microsoft suffers a setback in the antitrust lawsuit filed against it by the federal government when the presiding judge rules that Microsoft is a monopoly that deploys its marketing muscle to intimidate competitors.

• Two boys at Columbine High School in Littleton, Colo., bring weapons to school and shoot to death 12 students and a teacher before killing themselves. The event brings new demands for gun control and for an investigation into a wave of shootings in schools in the United States.

• John F. Kennedy Jr., son of the assassinated President Kennedy, dies with his wife Carolyn and her sister when a plane he is piloting crashes into waters near Martha’s Vineyard.

• Eleven members of the European Union begin using the euro, the EU’s new currency that, according to the plan, will replace national monies in the early 2000s.