Italy is located in Southern Europe and comprises the long, boot-shaped Italian Peninsula, the land between the peninsula and the Alps, and a number of islands including Sicily and Sardinia. Its total area is 301,230 km², of which 294,020 km² is land and 7,210 km² is water. Including islands, Italy has a coastline and border of 7,600 km on the Adriatic, Ionian, Tyrrhenian seas (740 km), and borders shared with France (488 km), Austria (430 km), Slovenia (232 km) and Switzerland; San Marino (39 km) and the Vatican City (3.2 km), both entirely surrounded by Italy, account for the remainder. The Apennine Mountains form the peninsula's backbone; the Alps form its northern boundary. The largest of its northern lakes is Garda (143 sq mi/370 km2); in the centre is Trasimeno Lake. The Po, Italy's principal river, flows from the Alps on the western border and crosses the great Padan plain to the Adriatic Sea. Several islands form part of Italy; the largest are Sicily (9,926 sq mi/25,708 km2) and Sardinia (9,301 sq mi/24,089 km2).
Italy is a volcanically active country, containing the only active volcano in mainland Europe. The country's volcanism is due chiefly to the presence, a short distance to the south, of the boundary between the Eurasian Plate and the African Plate. The magma erupted by Italy's volcanoes is thought to result from the upward forcing of rocks melted by the subduction of one plate below another.
There are several active volcanoes in Italy: Etna, the second-largest active volcano in Europe; Vulcano; Stromboli; and Vesuvius, the only active volcano on the mainland of Europe.
The climate in Italy is highly diverse and can be far from the stereotypical Mediterranean climate depending on the location. Most of the inland northern areas of Italy, for example Turin, Milan and Bologna, have a continental climate often classified as humid subtropical (Köppen climate classification Cfa). The coastal areas of Liguria and most of the peninsula south of Florence generally fit the Mediterranean stereotype (Köppen climate classification Csa). The coastal areas of the peninsula can be very different from the interior higher altitudes and valleys, particularly during the winter months when the higher altitudes tend to be cold, wet, and often snowy. The coastal regions have mild winters and warm and generally dry summers, although lowland valleys can be quite hot in summer.