Henry Wadsworth Longfellow wrote, “My soul is full of longing for the secrets of the sea, and the heart of the great ocean sends a thrilling pulse through me.” Ours is a water world where 2/3 of Earth’s solid surface lies beneath oceans and seas. For millennia, people have wondered what strange mysteries must lie beneath the ocean waves. In the last 50 years, new technologies have enabled researchers to systematically explore this mysterious universe. This course explores the geologic and oceanographic processes naturally occurring within the Earth’s oceans. The origin and geologic transformation of the Earth’s ocean basins over time and the origin and evolution of ocean waters will be examined. Astonishing bathymetric features will be discussed, including vast mountain chains, deep chasms, seamounts, giant deltas, landslides, and the role volcanism, seafloor spreading, and oceanographic currents have and continue to have in altering the seafloor and transporting thermal energy from the equator to the poles. Specific curious features will be discussed, including the world’s largest active volcano lying under the Pacific Ocean, and an erupting volcano at a depth of 4000m. The course is intended for those drawn and fascinated by the mysteries within the oceans. It will be taught in lecture format with discussion. Some background in the physical sciences would be useful, but is not required. Online video and reading material suggestions will be provided to help prepare students for each session.