It may seem odd to people who grew up in the single-family detached housing world of the postwar US, but there are cultures and societies around the world even

It may seem odd to people who grew up in the single-family detached housing world of the postwar US, but there are cultures and societies around the world even today where multi-family housing is common. See for example Casas de Vecindad, a typical form of housing in the US/Mexico borderlands for hundreds of years.