Bologna is the largest city of the Emilia-Romagna Region in Northern Italy. It is the seventh most populous city in Italy, located in the heart of a metropolitan area of about one million. The first settlements date back to at least 1000 BC. The city has been an urban centre, first under the Etruscans and the Celts, then under the Romans, then again in the Middle Ages, as a free municipality. Home to the oldest university in the world, An important cultural and artistic centre, its importance in terms of landmarks can be attributed to a varied mixture of monuments and architectural examples as well as works of art which are the result of a first class architectural and artistic history. Bologna is home to numerous prestigious cultural, economic and political institutions as well as one of the most impressive trade fair districts in Europe. In 2000 it was declared European capital of culture and in 2006, a UNESCO "city of music". The city of Bologna was selected to participate in the Universal Exposition of Shanghai 2010 together with 45 other cities from around the world. Bologna is also one of the wealthiest cities in Italy, often ranking as one of the top cities in terms of quality of life in the country: in 2011 it ranked 1st out of 107 Italian cities.