Delivered at the 20th IPHS conference in Hong Kong, this President's Address explores the role of society and of planning history in a changing world. It argues that the society has a long history of international, innovative, and inter-generational engagement. It proposes that planning history can help promote ecosystemic thinking, facilitate understanding of historic path dependencies and their impact on contemporary spaces and planning, and provide a foundation for activating for planning societally just futures. Together, the members of the society can help explore the role of history for future planning.