A volcanic crater is a bowl-shaped depression that forms at the summit of a volcano after an eruption. When magma erupts from the volcano, it can create a large opening, which may fill with water over time, forming a crater lake. The size and shape of a crater can vary depending on the type of eruption and the volcano's structure. Crater formations can be found in various types of volcanoes, including shield volcanoes, stratovolcanoes, and cinder cone volcanoes. Some famous examples of volcanic craters include Kilauea in Hawaii and Mount St. Helens in the United States. These craters can provide valuable information about volcanic activity and the geological history of the area.