Fertile river valleys: The first cradles for permanent settlements were river valleys. At roughly 10,000 BCE to 6,000 BCE, many regions across the world began to settle down in these areas for agriculture. The land in river values was fertile, with lots of nutrients in the soil for agriculture, from years of growing and dying foliage, as well as the current foliage that could be cleared for arable land. They also provide relatively reliable sources of water—some consistent (such as the Indus Valley with its predictable flooding), others more volatile (such as unpredictable Mesopotamian flooding).
Architecture, literature, the divine: While these areas followed the previously-described ways of developing into city-states and even budding first-wave empires (city-states conquering multiple city-states for tribute and slaves), they often had iconic cultural features. For example, the Mesopotamian city-states often had at the center step- pyramid-like temples known as ziggurats, and we all know the iconic architectural feature of Egypt and the Nile River Valley. Other areas, like the Indus Valley, also had magnificent cities that featured the harnessing of natural winds for cooling and ventilation, and early forms of drainage and sewers in Harappa.
Chavin and Olmec agriculture: In the Americas, the early river valleys that emerged were those of Olmec in Mesoamerica Chavin in the Andes. While the Olmec were known for influencing the future cultures of Mesoamerica with ball sports, blood rituals, and their iconic head statues, both of these civilizations thrived in part due to their agricultural innovations, such as terracing and intercropping.
Indus, Meso, Egypt, Nubia trade: Interregional trade, on a consistent basis, was first developed between the RVCs of the Indus Valley, Mesopotamia, and Egypt.
First-wave empires (Sumer, Akkad, Nineveh, Babylon): Competition for trade and resources drove many of the city-states to struggle for dominance (particularly in Mesopotamia).
Chinese Shang and Zhou Dynasty: In the Yellow River Valley, early Chinese civilization emerged, most notably with the Xia (2070 BCE), Shang Dynasty (1600 BCE) and Zhou Dynasty (1046 BCE).