Examines ten of the world's most unusual ocean ridges and trenches and presents information on how they were formed, the ways they can change over time, and the methods geologists use to study them.

Origin of the landform: Ocean ridges and trenches -- Mid-Atlantic Ridge, Atlantic Ocean -- San Juan de Fuca Ridge, Pacific Ocean -- The Mariana Trench, Pacific Ocean -- The Galapagos Rift, Pacific Ocean -- East Pacific Rise, Pacific Ocean -- Arctic Ridge, Arctic Ocean -- Iceland, North Atlantic Ocean -- The Java Trench, Indian Ocean -- Peru-Chile Trench, Pacific Ocean -- Red Sea, North Africa and the Middle East.