Perth Canyon is Australia’s largest submarine canyon (~1500 km2) and is the most significant seabed feature within the marine park. The canyon is valued particularly for its aggregations of diverse marine life, including Blue Whales and Humpback Whales. This video illustrates the diverse and complex geomorphology of Perth Canyon, where water depths range from 200 m to over 4000 m. Geomorphic features highlighted include 900 m high undersea cliffs, 1.8 km high landslides and evidence for sediment flows on the canyon floor. The location and physical characteristics of these features influences the biodiversity within the canyon, as illustrated by images from undersea video showing rocky canyon walls that are habitat for delicate and rare marine fauna, including deepwater corals and glass sponges. Examples of other marine life are also shown, as observed by researchers using baited underwater video at the head of Perth Canyon where upwelling currents supply nutrient-rich waters. Images courtesy of University of Western Australia.