a period of 1,000 years, or the time when a period of 1,000 years ends
Stonehenge is believed to have been built about 5 millenniums ago.
The year 2000 marked the beginning of a new millennium.
Celebrations worldwide welcomed the new millennium with fireworks and festivities.
Some ancient structures have stood for over a millennium, showcasing enduring architecture.
Archaeologists study artifacts to understand cultures that flourished in past millennia.
