Lombardy is one of the twenty administrative regions of Italy, in the northwest of the country, with an area of 23,844 square kilometres (9,206 sq mi). About 10 million people, forming one-sixth of Italy's population, live in Lombardy and about a fifth of Italy's GDP is produced in the region, making it the most populous and richest region in the country and one of the richest regions in Europe. Milan, Lombardy's capital, is the second-largest city and the largest metropolitan area in Italy.