The Yearbook of Transnational History is dedicated to disseminating pioneering research in the field of transnational history. This sixth volume investigates the treatment of tangible and intangible heritage sites created before and after the advent of nation states and in spaces that are not under the control of nation states. Contributors discuss the appropriation of heritage sites that originated in the era of the Crusades by modern nation states, the lack of national appropriation in the case of transnational sealing sites in Antarctica, the process of recognizing transnational heritage sites in the case of assembly halls created by the transnational labor movement, and the treatment of potential heritage sites in outer space.