Now that you've learned a little about the features found along the shore , let's explore the topography that extends from the shoreline to the ocean bottom. The topography of the ocean floor is very diverse. The seafloor is where you can find the tallest mountains on Earth, as well as the deepest canyons (the Marianas Trench on the ocean floor is deeper than the Grand Canyon). The ocean floor also contains gently sloping margins and long flat plains. The next few pages will describe features found on the continental margin and the deep ocean floor - we'll start at the coastline and extend outward to the bottom of the ocean.