Using high-resolution models and the Piz Daint supercomputer, researchers have discovered anomalies deep within the Earth's mantle that appear to be remnants of submerged tectonic plates. These anomalies are located beneath large oceans and within the interiors of continents, far from current plate boundaries. The discovery challenges current theories about plate tectonics and raises questions about Earth's internal dynamics and the geological evolution of the planet. The researchers used full waveform inversion and the powerful Piz Daint supercomputer to uncover these hidden structures. Despite the discovery, the exact nature of these anomalies remains unknown.