Understanding the human brain is one of the greatest challenges facing 21st century science. If we can rise to the challenge, we can gain profound insights into what makes us human, develop new treatments for brain diseases, and build revolutionary new computing technologies that will have far reaching effects, not only in neuroscience. Scientists at the European Human Brain Project, the Allen Institute for Brain Science, and the U.S. BRAIN initiative, are developing new paradigms for understanding how the human brain works in health and disease. This symposium highlights pioneering researchers working to uncover the circuitry of human cognition, identify the genetic roots of disease, unlock the power of Big Data for diagnosis, build a new generation of computing hardware inspired by the brain, and perform revolutionary experiments on a realistic model of the brain that could never be done in animals or humans. It is also the opportunity to discover global initiatives towards understanding the brain.