THINK DEEP pioneers a creative practice driven interdisciplinary approach to the underground. It begins from the dual premise that, firstly the underground (or subterranean) is both the site of current environmental concerns (e.g. extraction), and the setting for developing solutions to these concerns. But that secondly, currently we lack approaches that adequately understand the underground, its current use and conservation, and its future possibilities. Underground scholars have long argued that what is needed is an interdisciplinary approach, as yet, however, where interdisciplinarity has been achieved, it has largely brought together science and social science. Unconventionally, THINK DEEP situates creative practices (such as visual art or participatory theatre) together with arts and humanities theories as the cornerstone of an interdisciplinary response to three pressing underground research problems: 1. How to sense the underground, an often inaccessible environment? 2. How to contend with varied underground imaginations, which shape underground understanding, use and conservation? 3. How to understand the speculative nature of ‘knowing’ the underground? It will address these problems through global case studies from three fields of underground research: geoscience, underground urban studies, and geoconservation. Its unconventional ambition enables THINK DEEP to deliver a timely and distinctive new contribution to underground scholarship that will transform the field’s future research directions. Furthermore, the project’s pioneering approach will bring about a step-change in relations between creative practices and research more generally. In understanding and evaluating the creative practice and research relations that sit at its heart, THINK DEEP enables ground-breaking understandings of these relations, and of their profound possibilities with respect to a range of research fields, including those which engage pressing environmental issues.