This chapter aims to conceptualise a dialectical and critical understanding of cosmopolitanism from below, from the potential of the cities to forge an inclusive cosmopolitanism. It does not mean that the cities guarantee per se the existence of diversity and inclusiveness. In our conceptualisation of urban cosmopolitanism, the city becomes the site to foster translocal solidarities, dialectically connecting particularism and universalism and expanding the political community. Moreover, this framework allows us to analyse new forms of global networking of solidarity/sanctuary cities. We argue that such networks may have a transformative potential based on local solidarities as well as the ability to both develop new imaginaries and materialise these through practices. We use two cases to illustrate this point, namely the Fearless Cities movement and the World Social Forum on Migration.