Most volcanoes form at the boundaries of Earth's tectonic plates, which are huge slabs of crust and upper mantle that fit together like puzzle pieces. Think of these plates as massive rafts floating ...

Some volcanoes, such as the Cascade volcanoes up in Washington and Oregon, are of the type called a stratovolcano. These steep volcanoes sometimes erupt explosively and other times have calmer lava ...

Learn how Mount Etna stands apart from most volcanoes, having been formed by pockets of magma held in Earth's upper mantle. Europe’s tallest active volcano, Mount Etna, may belong to an obscure group ...