Millions of years ago, a series of volcanoes began erupting on the deep floor of the Pacific Ocean. Cones of volcanic debris built up bit by bit and at last broke through the surface of the water. Time after time they were beaten dorm by pounding seas and time after time the undersea volcanoes erupted and added new material to the growing mountains. The sea was at last defeated and a series of volcanic islands appeared in the Pacific.

This gift of dry land from the undersea volcanoes is the Hawaiian Islands. The Azores islands in the Atlantic Ocean also were formed by undersea volcanoes. Countless other volcanoes erupt from the sea bed, but most of them fume and smoulder for ages without ever reaching the surface.