Pisa is a city located in Tuscany, Italy. Situated at the mouth of the Arno River at the Mediterranean Sea, Pisa existed before ancient Roman times, and was one of Italy’s 4 Marine Republics (Genoa, Amalfi, and Venice were the other 3). Pisa is best known for the Leaning Tower of Pisa, built in1173. Other tourist sites in Pisa include the Duoma, the Baptistry, the Camposanto, and Knights’ Square. Pisa was home to Galileo Galilei. The estimated population of Pisa is 90,000.