While many volcanoes are mountains, it is possible for a volcano to erupt from a vent in any type of land form. Over time, volcanoes become mountains by depositing their discharge around them in ever-increasing layers. Not all mountains are volcanoes.
Most famous volcanoes are in conical mountains, which look like mountains with craters instead of peaks. Well-known volcanoes with this shape include Mount St. Helens, Mount Vesuvius and Mount Fuji. Underwater volcanoes are vents on the surface of the ocean that can develop into pillar- or mountain-like shapes. Other types of volcano shapes include shield volcanoes, lava domes and subglacial volcanoes.