What event (revolution) allowed people to build cities? Briefly describe the characteristics of Civilization. What are some River Valley Civilizations we have discussed?

developed new techniques in stone cutting, copper, bronze and other building material.

Explanation:

The civilization of Indus Valley occurred in the early 3300-1300 BCE, the path of civilization extended along the Indus river to Afghanistan into Pakistan and northwest parts of India.  Harappa and Mohenjodaro were the two most important cities of civilization. The Indus valley civilization was noted for their urban planning, use of the brick system and drainage system for irrigation and domestic use. Harappa was the largest city and Mohenjo-Daro was major urban centers with sophisticated engineering and design.