In contemporary history, the third millennium is a period o time that accordin tae offeecial sources, such as the Unitit States Naval Observatory, began on Januar 1, 2001, and will end on December 31, 3000, o the Gregorian calendar.
- United States Naval Observatory, "The 21st Century and the 3rd Millennium:When Did They Begin?" (Washington, DC, June 14, 2011).
- "When and where did the new Millennium officially start, and why?". Royal Observatory Greenwich