brought to the city new economical and social energy. In the early 21st century, Milan underwent a series of sweeping redevelopments over huge former industrial areas. Two new business districts, Porta Nuova and CityLife, were built in the space of a decade, radically changing the skyline of the city. Its exhibition centre moved to a much larger site in Rho. The long decline in traditional manufacturing has been overshadowed by a great expansion of publishing, finance, banking, fashion design, information technology, logistics and tourism. The city's decades-long population decline seems to have partially reverted in recent years, as the gained about 100,000 new residents since the last census. The successful re-branding of the city as a global capital of innovation has been instrumental in its successful bids for hosting large international events such as 2015 Expo and 2026 Winter Olympics. Geography Topography Milan is located in the north-western section of the Po Valley, approximately halfway between the river Po to the south and the foothills of the Alps with the great lakes (Lake Como, Lake Maggiore, Lake Lugano) to the north, the Ticino river to the west and the Adda to the east. The city's land is flat, the highest point being at above sea level. The administrative covers an area of about , with a population, in 2013, of 1,324,169 and a population density of . The Metropolitan City of Milan covers and in 2015 had a population estimated at 3,196,825, with a resulting density of . A larger urban area, comprising parts of the provinces of Milan, Monza e Brianza, Como, Lecco and Varese is wide and has a population of 5,270,000 with a density of . The concentric layout of the city centre reflects the Navigli, an ancient system of navigable and interconnected canals, now mostly covered. The suburbs of the city have expanded mainly to the north, swallowing up many along the roads towards Varese, Como, Lecco and Bergamo. Climate Milan features a mid-latitude, four-season humid subtropical climate (Cfa), according to the Köppen climate classification. Milan's climate is similar to much of Northern Italy's inland plains, with hot, humid summers and cold, foggy winters. The Alps and Apennine Mountains form a natural barrier that protects the city from the major circulations coming from northern Europe and the sea. During winter, daily average temperatures can fall below freezing () and accumulations of snow can occur: the historic