We use the most advanced accelerator-based x-ray sources to follow and visualize dynamics on the nanometer scale. At the intensity frontier, we use femtosecond x-ray pulses to image individual nanoparticles with single shots. At the time resolution frontier, we pursue novel experimental approaches and methodologies to follow the electronic evolution of atoms, molecules, and nanometer-sized structures on the femtosecond time scale. We work closely with experimental and theory groups around the globe to develop novel x-ray spectroscopy approaches and to model x-ray induced processes.