In the mid eleventh century AD, Cahokia emerged as a substantial Mississippian urban centre. To the east, a shrine-complex known as the Emerald Acropolis, marking the beginning of a processional route to the city, also flourished. Excavations and geophysical survey of the monumental landscape around this site suggest that lunar cycles were important in the orientation of structures and settlement layout. They further indicate that water played a significant role in the ritual activities associated with the closure and abandonment of individual structures. The contemporary development of these sites suggests an intrinsic connection between them, and provides early evidence of the importance that the moon and water came to assume in Mississippian culture.

Meticulous survey of the banks, channels and reservoirs at Angkor shows them to have been part of a large scale water management network instigated in the ninth century AD. Water collected from the hills was stored and could have been distributed for a wide variety of purposes including flood control, agriculture and ritual while a system of overflows and bypasses carried surplus water away to the lake, the Tonle Sap, to the south. The network had a history of numerous additions and modifications. Earlier channels both distributed and disposed of water. From the twelfth century onwards the large new channels primarily disposed of water to the lake. The authors here present and document the latest definitive map of the water network of Angkor.