This European Architecture History Network (EAHN) Thematic Conference invites discussion and provides a setting to compare the ways in which power relations, national identities and practices of empire building conditioned and materialized in architecture and urban spaces from St. Petersburg to Helsinki, Moscow to Warsaw, Kyiv, Kharkiv, Tbilisi, Astana, Tashkent and beyond in a long time perspective from the 18th to the 21st century. It sets to revise and de-colonize the histories of architecture, cities and environments built under the influence of the Russian Empire, the Soviet Union and other formations in Eastern Europe and Northern Eurasia. The “states in between” here refers to the geographic areas on the borders or within large empires – be they indigenous lands, colonized nation states or neighbours trying to stay independent – but, also to various nuances of exchange and impact on culture, ideology, and politics, as well as ethnic, social, class and gender identities.