This Element describes and synthesizes archaeological knowledge of humankind's first cities for the purpose of strengthening a comparative understanding of urbanism across space and time. Case studies are drawn from ancient Mesopotamia, Europe, Asia, Africa, and the Americas. They cover over 9000 years of city building. Cases exemplify the 'deep history' of urbanism in the classic heartlands of civilization, as well as lesser-known urban phenomena in other areas and time periods. The Element discusses the relevance of this knowledge to a number of contemporary urban challenges around food security, service provision, housing, ethnic co-existence, governance, and sustainability. This study seeks to enrich scholarly debates about the urban condition, and inspire new ideas for urban policy, planning, and placemaking in the twenty first century.