New Year's Eve 2000 marked the transition from the 20th century to the 21st century, celebrated globally with great enthusiasm. Many people were concerned about the potential effects of the Y2K bug, which was thought to cause computer malfunctions as the year changed. Major cities, including New York City and Sydney, hosted large public celebrations featuring fireworks and concerts. The iconic Times Square ball drop in New York attracted thousands of spectators, while other countries also held their own unique festivities to welcome the new millennium.