The 2nd millennium was the thousand-year period that commenced on January 1, 1001 and ended on December 31, 2000, encompasses the High Middle Ages, the Renaissance, the Early Modern Age, the age of Colonialism, industrialization, the rise of nation states, and culminates in the 20th century with the impact of science, widespread education, and universal health care and vaccinations in many nations. The centuries of expanding large-scale warfare with high-tech weaponry (of the World Wars and nuclear bombs) are offset by growing peace movements from the United Nations, the Peace Corps, religious campaigns warning against violence, plus doctors and health workers crossing borders to treat injuries and disease and the return of the Olympics as contest without combat.

Scientists prevail in explaining intellectual freedom; humans take their first steps on the Moon during the 20th century; and new technology is developed by governments, industry, and academia across the world, with education shared by many international conferences and journals. The development of movable type, radio, television, and the internet spread information worldwide, within minutes, in audio, video, and print-image format to educate, entertain, and alert billions of people by the end of the 20th century.