The city is part of the Campo de Calatrava natural region, a transitional region between the "Montes" and La Mancha, remarkable in the context of the Iberian Peninsula because of its volcanic origin. The plaza del Pilar is precisely built on the centre of a shallow volcanic maar. As Ciudad Real itself was the capital of the province of La Mancha in the 18th century, the whole province of Ciudad Real is often considered as part of La Mancha in a wider sense.