Explosions are a pressing and pervading threat in the modern world. Terrorist events such as the 2017 Manchester Arena bombing, large-scale industrial accidents such as the 2020 Beirut explosion, and the current conflict in Ukraine, have highlighted a key gap in our knowledge: we do not we do not yet understand how blast waves propagate and interact with multiple obstacles in complex environments. Accordingly, we cannot yet predict the loading from such events, and our ability to determine the consequences relating to risk, structural damage, and casualty numbers, is severely limited. Current numerical tools for predicting blast loads in complex environments are either overly simplistic, or physics-based numerical tools which have been hitherto developed in the absence of experimental validation data. Clearly, progress in this area is limited and will remain so until we have the ability to experimentally measure the output from explosions occurring in settings of varying complexity at varying scales. This proposal will see the development of an ambitious and unique experimental facility, MicroBlast, for ultra-small-scale studies of blast propagation in complex environments, making use of rapid prototyping and 3D printing to generate true replica test specimens. MicroBlast will be a new state-of-the-art apparatus for data-rich, high spatial/temporal resolution, multi-parameter, full-field measurements of blast loading using a combination of pressure sensors, stereo high speed video cameras, and medium-wave infra-red cameras. This facility will be a step-change in our ability to perform rapid, precision experiments in explosive load quantification; the blast equivalent of a wind tunnel or shaking table test. We aim to study the fundamental mechanisms governing blast load development in complex environments, and set the agenda for future research in this area. Are explosions in crowded environments repeatable and deterministic, or are they highly sensitive to small changes in input parameters? What are the consequences for numerical modelling tools and experimental design? We aim to develop the next generation of predictive approaches for blast in urban environments, and to collectively raise the scientific benchmark of load prediction and structural damage assessment.