Over 50 years ago, the acceptance of plate tectonics led to a new paradigm in the Earth Sciences. As a result, we now better understand why earthquakes occur where they occur and how volcanoes are formed. However, what defines a tectonic plate is still ambiguous. To understand better the formation of tectonic plates, nearly 80 ocean-bottom sensors were deployed for a year across the equatorial region of the Mid-Atlantic Ridge. This ambitious experiment is providing striking new images of plates and fresh insights into the forces that move them across the surface of the Earth.