Here is a brief resume of three great ancient civilizations, the barebone stuff on just about how long they lasted. The actual dates mentioned are open to question- but is ther much to argue about if I state that they lasted about three millenia ?
1. Nile: The Nile valley civilization of ancient Egypt is usually regarded as dating from 3100 BC and ending in 31 BC with the defeat of Antony and Cleopatra by Octavian (Caesar Augustus). That is about 3000 years.
2. Mesopotamia: Almost from 9000 BC when the first agricultural societies were formed to 500 BC when Cyrus, the Persian warrior conquered Babylon. However if Sumerian occupation of the Euphrated basin is taken as the starting point, this comes to about 3000 years again, because the Sumerian period began around 3500 BC.
3. Indus: Probably the shortest of the three, Indus Valley civilization is believed to have lasted from 3500 BC to 1750 BC. That is about 2000 years.