Unified Indus Valley civilisation. c. 2500 BC: The state of Assyria is established. c. 2500 BC: Excavation and development of the Hypogeum of Ħal-Saflieni at Paola, Malta, a subterranean temple complex subsequently used as a necropolis. c. 2500 BC–2200 BC: Incised panel "Frying pan", from Syros, Cyclades is made; it is now at the National Archaeological Museum, Athens. c. 2500 BC–2200 BC: Two figures of women, from the Cyclades, are made; they are now at Museum of Cycladic Art, Athens. Dynasty of Lagash in Sumer. 2474 BC–2398 BC: Golden age of Ur in Mesopotamia. c. 2498 BC: Fifth Dynasty of Egypt, reign of Userkaf. c. 2492 BC: The Armenian patriarch Hayk defeats the Babylonian king Bel (legendary account). c. 2345 BC: Sixth Dynasty of Egypt, reign of Teti. 2334 BC: Sargon of Akkad conquers Mesopotamia, establishing the Akkadian Empire. c. 2300 BC: C-Group pastoralists arrive in Nubia. c. 2181 BC: Seventh and Eighth Dynasty of Egypt (2181–2160). c. 2160 BC: Ninth Dynasty of Egypt, reign of Akhtoy Meryibtowe. c. 2130 BC: Tenth Dynasty of Egypt, reign of Meryhathor. c. 2134 BC: Eleventh Dynasty of Egypt, reign of Mentuhotep I. Megalithic, Corded Ware culture and the Beaker flourish in Europe. Sumerian poetry, lamenting the death of Tammuz, the shepherd god. Sumerian cuneiform writing (reduces pictographs still in use to about 550 BC). Major religious festival in Sumeria celebrates victory of god of spring over goddess of chaos. Earliest Trojan culture. Glass beads in Egypt. The world's last surviving mammoth population, on Wrangel Island in the Arctic Ocean, goes extinct, sometime between 2500 and 2000 BC. c. 2070 BC–1600 BC: The first dynasty in traditional Chinese historiography--Xia dynasty begins in China. Inventions, discoveries, introductions The oldest documented evidence of the practice of meditation are wall arts in the Indian subcontinent. c. 3500 BC: Indus script develops in Indus Valley civilization. Stepwell: Earliest clear evidence of the origins of the stepwell is found in the Indus Valley civilisation's archaeological site at Mohenjodaro in Pakistan and Dholavira in India. Squat toilet: toilet platforms above drains, in the proximity of wells, are found in several houses of the cities of Mohenjodaro and Harappa. Pottery develops in Americas (30th century BC). c. 3000 BC: Potter's wheel appears in Mesopotamia. 2900 BC–2400 BC: Sumerians invent phonogram (linguistics). 2650 BC: Reservoirs, script, metals and pottery used in the city of Dholavira in Indus Valley civilization. c. 2300 BC: