The ARNO and the Tiber are two rivers that flow into the Tyrrhenian Sea. The ARNO is a river in central Italy, originating near Florence and flowing through Pisa before emptying into the Tyrrhenian Sea. The Tiber is the third-longest river in Italy, originating in the Apennine Mountains and flowing through Rome before emptying into the Tyrrhenian Sea. Both rivers are important to the history and culture of Italy, and have been used for transportation, irrigation, and other purposes for centuries.