Now fundamental to our understanding of Earth science, the theory of continental drift was highly controversial – if not outright derided by the majority of the scientific community – when the German geophysicist Alfred Wegener first proposed it in 1912. This lively short animation from the Royal Institution chronicles how the American geologist Marie Tharp’s tireless and brilliant work helping to map the ocean floor during the mid-20th century – which included battling endemic sexism – forced a massive paradigm shift that led to plate tectonics gaining widespread acceptance among scientists.