Maar

Maar, pronounced "mar", is a big hole in the ground that is created when super hot lava from a volcano meets with water, usually underground. When the hot lava touches the water, it turns into steam that tries to escape, but since the water is surrounding it, the steam builds up pressure and explodes outwards, creating a big hole in the ground called a maar. It's kind of like when you shake a soda bottle and then open it up really quickly, making the fizz shoot out. Maars come in different sizes, some can be as big as a football field and some can be really small. They are found all around the world and are sometimes filled with water to make a beautiful lake. Even though maars are formed by volcanic activity, they are usually not dangerous to people as they don't erupt like a regular volcano.