31st century BC
The 31st century BC was a century that lasted from the year 3100 BC to 3001 BC.
Events
Image:Malta Hal Tarxien BW 2011-10-04 12-41-38.JPG|200px|thumb|Spiral design altar block from the Tarxien Temples of Malta, uncovered by Sir Themistocles ZammitImage:NarmerPalette ROM-gamma.jpg|180px|thumb|Front and back sides of Narmer Palette, this facsimile on display at the Royal Ontario Museum, in Toronto, Ontario, Canada. The palette depicts Narmer unifying Upper Egypt and Lower Egypt.
- c. 3100 BC: Polo was first played in Manipur state.
- c. 3100 BC?: The Anu Ziggurat and White Temple are built in Uruk.
- c. 3100 BC?: Predynastic period ends in Ancient Egypt.
- c. 3100 BC?: Early Dynastic period starts in Ancient Egypt.
- c. 3100 BC?: The first temple of Tarxien is in use by the Neolithic inhabitants of Malta.
- c. 3100 BC?: First stage in the construction of Stonehenge.
- c. 3100 BC: Oldest adobe building in the Americas was built in what is now Peru.
- c. 3100 BC – 2600 BC: Skara Brae, Orkney islands is inhabited.
- c. 3090 BC: Narmer unifies Upper and Lower Egypt into one country; he rules this new country from Memphis.
- c. 3051 BC: The oldest currently living organism, a Great Basin bristlecone pine, undergoes germination in the White Mountains of California.
Inventions, discoveries, introductions
- Drainage and sewage system in the Indus Valley
- Dams, canals, stone sculptures using inclined plane and lever in Sumer and the Tigris–Euphrates Valley
- Copper was in use, both as tools and weapons.
- Senet, one of the oldest-known board games in the world is invented.
- c. 3100 BC – Invention of writing in Mesopotamia and Egypt
- The Sydney rock engravings date to around 3000 BC.