Castillo de Calatrava La Vieja in Carrión de Calatrava

You're standing at Calatrava la Vieja, Old Calatrava, just outside the village of Carrión de Calatrava. Today you'll mostly see the remains of a medieval fortress. But back in the Middle Ages, this was the only important city in the whole Guadiana valley. Picture the roads that ran past here, south to Córdoba and north to Toledo. Whoever held this spot controlled those routes.