There are four main types of volcanoes: shield volcanoes, stratovolcanoes, cinder cone volcanoes, and lava domes. Shield volcanoes have broad, gentle slopes and are built from low-viscosity lava that flows easily. Stratovolcanoes, also known as composite volcanoes, have steeper profiles and are formed from alternating layers of lava and ash. Cinder cone volcanoes are the smallest type, characterized by steep slopes and built from volcanic debris ejected during eruptions. Lava domes are formed from the slow accumulation of viscous lava, creating a dome-shaped structure. Each type has unique features and eruption styles.