The geography of Vatican City is unique due to the country's position as an urban, landlocked enclave of Rome, Italy. With an area of 49 ha (121 acres, or 0.19 sq mi), and a border with Italy of 3.5km, it is the world's smallest independent state. Outside the Vatican City, thirteen buildings in Rome and Castel Gandolfo (the pope's summer residence) enjoy extraterritorial rights (one building, the Paul VI Audience Hall, straddles the border, but its Italian portion has extraterritorial rights). The country contains no major natural resources, and no known natural hazards other than those that affect Rome in general, such as earthquakes. Climate The city state has the same climate as Rome: temperate, mild, rainy winters (September to mid-May) with hot, dry summers (May to September). Terrain Vatican City sits on a low hill. The hill has been called the Vatican Hill (in Latin, Mons Vaticanus) since long before Christianity existed. An Etruscan settlement, possibly called Vatica or Vaticum, may have existed in the area generally known by the ancient Romans as "Vatican territory" (vaticanus ager), but if so no archaeological trace of it has been discovered. Extreme points This is a list of the extreme points of Vatican City: the points that are farther north, south, east or west than any other location, as well as the highest and lowest points. North: at the intersection of the Viale Vaticano and the Via Leone IV () South: at the intersection of the Via della Stazione Vaticana and the Via di Porta Cavalleggeri () West: at the intersection of the Viale Vaticano and the Via Aurelia () East: easternmost edge of Saint Peter's Square () The lowest point in Vatican City is an unnamed location at . The highest point is another unnamed location at . The tallest building is St. Peter's Basilica, at 138 metres (453 ft). Land use The nature of the estate is fundamentally urban and none of the land is reserved for significant agriculture or other exploitation of natural resources. The city state displays an impressive degree of land economy, born of necessity due to its extremely limited territory. Thus, the urban development (i.e., buildings) is optimized to occupy about half of the total area, while the rest is reserved for open space, including the Vatican Gardens. The territory holds many diverse structures that help provide autonomy for the sovereign state, including a rail line