Which volcano has the tallest lava dome in the world?

The question of the "largest" or "tallest" lava dome depends on whether scientists measure height, volume, or preserved size. One of the best-known large lava domes is Santiaguito in Guatemala, which has grown continuously since the 1920s, while the Chichón and Novarupta systems also produced significant dome complexes. Lava domes form from viscous lava that piles up near the vent instead of flowing far away. Because they can collapse and generate deadly pyroclastic flows, domes are a major volcanic hazard. Their growth is closely watched by volcanologists around the world.