The River Tajo, also known as the Tagus, is the longest river in the Iberian Peninsula, flowing approximately 1,007 kilometers. It originates in the Sierra de Albarracín mountains in Spain and travels through the country before entering Portugal, where it eventually empties into the Atlantic Ocean at Lisbon. The river plays a significant role in the regions it traverses, providing water for agriculture and serving as a vital transportation route. Along its banks, several cities, including Toledo and Lisbon, have developed, benefiting from the river's resources and scenic beauty.