This article is a result of a comprehensive and international literature review of corresponding sociological and urban studies publications on functions of museums in a city. A two-dimensional taxonomy of functions is presented. In the first dimension cities are considered in physical space (here labeled as Firstspace), mentalspace (Secondspace) and political space (Thirdspace). In the second dimension, museum functions are dichotomized in manifest functions that are intended and openly propagated, and latent functions that are hidden from the public and often unintended. This article will list examples for museum functions in First-, Second-, and Thirdspace from Europe and America. Museums shape cities, and are themselves shaped by cities in multiple ways.