In the early 1990s, Walter Munk (APS 1965) and his colleagues organized a global experiment that they hoped might solve a major problem facing the planet—how to measure global warming of the oceans. In this episode, learn about how Walter Munk came to be known as the “Einstein of the oceans” and how he built a team of scientists to try to answer a simple but surprisingly difficult question—what was the temperature of the oceans across the globe?