Ecumenopolis

An ecumenopolis is a world city or planet-wide city. As a type 0 civilization progresses towards 1, urban areas and megalopolises would eventually fuse and there could be a single continuous worldwide city as a progression from urbanization, population growth, transport and human networks.

A planet spanning city is only sustainable if there is a sufficient and steady import of food and resources from nearby planets or star systems. This is more plausible for a Type-1 civilization.

An example of an ecumenopolis is Coruscant.