These landforms represent the destructive phase of volcanism. A crater is typically small (less than 1 km wide) and is the primary exit point for magma and gases. In contrast, a caldera is a massive feature (often exceeding 10 km) formed by structural failure. When a huge volume of magma is erupted rapidly, the “roof” of the magma chamber loses its support and sinks. Famous examples include Crater Lake in Oregon and the Yellowstone Caldera. These depressions often fill with water over time, forming picturesque but geologically significant volcanic lakes.