Europe’s tallest and most active volcano is growing—fast! Italy’s Mt. Etna recently went through a huge series of eruptions. Molten rock exploded out of its crater more than 50 times over 6 months last year.

All of these eruptions caused the volcano to grow by about 100 feet, bringing its total height to a whopping 11,013 feet. “Material is thrown out of the crater and falls back around the crater,” said volcanologist Boris Behncke, from the National Institute of Geophysics and Volcanology in Italy. “It piles up gradually, so that the volcano becomes a mound, then a hill, and then a growing mountain.” Behncke says these eruptions teach us that “the whole system of a volcano changes with each eruption, like we change with every experience we have.”