Under the Moors it was of great importance as the key of the Ebro valley.
The principal rivers entering the Mediterranean directly are the Nile from Africa, and the Po, Rhone and Ebro from Europe.
But some parts of the old town have been rebuilt, and there is a modern suburb on the opposite side of the Ebro.
The city is connected with Barcelona and Valencia by the coast railway, and with Saragossa by the Ebro valley line; it is also the terminus of a railway to San Carlos de la Rapita on the Mediterranean.
On the 26th of October 1808, when Moore's troops had left Lisbon to join Baird, the French still held a defensive position behind the Ebro; Bessieres being in the basin of Vitoria, Marshal Ney north-west of Logrono, and Moncey covering Pampeluna, and near Sanguessa.