Some of the main features that you would be able to see within these 4 zones are:

Submarine mountains and volcanoes: Submarine mountains and volcanoes form the most dramatic features of the seafloor and the longest mountain chain on Earth, which stretches 60,000 km around the globe. They are mostly located where plates are being pulled apart from each other at mid-oceanic ridges. The largest mountain on Earth is not Mount Everest, but Mauna Kea, part of the Hawaiian volcanic island chain, rising 10,000 m above the seafloor.

Seamounts and guyots: Seamount and guyots are isolated volcanic peaks that do not extend above sea level. There are thousands of them, 10,000 alone in the Pacific Basin.

Trenches: Where two crustal plates collide, one plate is dragged down into the Earth, and very deep subduction trenches are formed.The deepest place in the ocean is the Marianas Trench, western Pacific Ocean, at 11,304 m depth.

Canyons: Have you heard about the Grand Canyon, a famous landmark in the United States of America? Imagine such a huge feature under water. Impossible? Not at all! The largest known submarine canyon is up to 370 km long and 3,500 m deep! Submarine canyons are generally found on continental slopes.

Landslides: With so much sediment building on the seafloor, it sometimes happens that the sediment becomes unstable and fails as a landslide. Submarine landslides are quite common and they can be extremely large. The scar left by the Storegga Slide, one of the largest submarine landslides known, is as big as the country of Portugal! Submarine landslides are generally triggered by the huge weight of sediment built up or by earthquakes.

3D image of massive Storegga slide possibly caused by a gas hydrate melt-down -- resulted in a tsunami that drowned Scotland 7,000 years ago. Image courtesy of Deep East 2001, NDWP, NOAA/OER.

Bedforms: Have you ever seen sand dunes on a beach or in a desert? Bedforms are similar features on the seafloor that are formed by slow moving currents that sculpt the sand and mud into giant dunes.

Coral reefs: Some seafloor features are formed by biological processes, and the most famous of these is the Great Barrier Reef. This reef is found in Australia and is 2000 km long. It consists of numerous mounds and reefs formed by coral communities.