The move online of almost all meetings in 2020 in the wake of the COVID-19 pandemic threw into sharp relief the taken-for-granted centrality of conferences within scientific culture. While its impact on science has yet to be fully grasped, for the authors of this special issue, this situation held heuristic power for understanding the meanings and functions, now and historically, of international scientific conferencing. Ongoing discussions in the academic world about the pros and cons of virtual meetings bring out the central place of presence in these events and its mediation across space and time by modern infrastructures and technologies. From their rise in the mid-nineteenth century to the experiences of the present day, as well as in imagined futures, international conferences have been about communication. Following James Carey, they can be considered both as places for sharing knowledge and as rituals aimed at fostering and performing communities.