Mount Etna, Europe's most active volcano, has been erupting regularly since 2011. However, the latest series of explosions, which began on February 16, 2021, has been particularly noteworthy. Emanating from the youngest of the volcano's four craters — the Southeast Crater— they have spewed spectacular fountains of lava as high as 0.9 miles (1.5 kilometers). To put it in perspective, that is about three times the height of One World Trade Center, the tallest building in the United States.