High-brilliance x-ray sources (x-ray free-electron lasers or diffraction-limited storage rings) allow the visualization of ultrafast processes in a 2D manner using single exposures. Current 3D approaches scan the sample using multiple exposures, and hence they are not compatible with single-shot acquisitions. Here we propose and verify experimentally an x-ray multi-projection imaging approach, which uses a crystal to simultaneously acquire nine angularly resolved projections with a single x-ray exposure. When implemented at high-brilliance sources, this approach can provide volumetric information of natural processes and non-reproducible samples in the micrometer to nanometer resolution range, and resolve timescales from microseconds down to femto-seconds. (c) 2018 Optical Society of America under the terms of the OSA Open Access Publishing Agreement