In this episode of Earth SciShow, we explore the extraordinary eruption of the Hunga Tonga–Hunga Haʻapai volcano in January 2022, which created the tallest volcanic plume ever recorded. We talk to Dr Simon Proud, a senior scientist at Oxford University and one of the authors of a new study that used satellite images and a technique called 'the parallax effect' to measure the height of the plume. We also discuss the implications of this eruption for the global stratospheric composition and climate.