It has long been argued by poets, ancient Egyptians and cardiologists that the heart is the most important organ. They’re probably right - cardiovascular-related diseases are the leading cause of death worldwide. But to improve diagnosis and treatment of such diseases, we need to understand the healthy heart. One way to study healthy and diseased hearts is to use animal models, such as zebrafish, that have some degree of similarity to humans. But how do you record information about the living, beating heart without interrupting the heart beat or stopping the heart altogether? Find out about recent research in the Imaging Concepts Group at the University of Glasgow that has provided a solution to this problem - a solution that is enabling us to see biology never before seen.