The feature that provides evidence that a volcano existed in the past is calderas. A caldera is a large volcanic crater that is typically formed by the collapse of a volcano's cone or central vent following an eruption. These calderas can often be observed as circular depressions on the Earth's surface and are strong indicators of past volcanic activity. To identify calderas as evidence of a past volcano, one can conduct geological surveys, examine topographic maps, or even visually inspect the landscape to look for circular or elliptical depressions that resemble volcanic craters.
