The fundamental reason for all these mountains on the western side of the Americas is the steady movement of the great landmasses away from Eurasia and Africa. The process of continental drift is fuelled by the production of sea-floor material at the mid-Atlantic trench. The landmasses of the Americas have buckled the edges of the Pacific plates, resulting in the continual volcanic build-up of mountains on the western side of the continents. The Cascade Volcanic Arc made its first appearance 36 million years ago. The major volcanic peaks today were born in the last 1.6 million years. More than 3,000 vents erupted during the most recent volcanic episode that began 5 million years ago. As long as subduction continues, new Cascade volcanoes will continue to rise.