Bologna is the lively, historic capital of the Emilia-Romagna region, in northern Italy. Piazza Maggiore is a sprawling plaza lined with arched colonnades, cafes and medieval and Renaissance structures, such as City Hall, the Neptune Fountain and the Basilica of San Petronio. Among several medieval towers is the leaning Asinelli Tower, which is open for climbs. The first settlements date back to at least 1000 BC. The city has been an urban centre, first under the Etruscans (Velzna/Felsina) and the Celts (Bona), then under the Romans (Bononia), then again in the Middle Ages, as a free municipality (for one century it was the fifth largest European city based on population). Home to the oldest university in the world, University of Bologna, founded in 1088. Bologna has a humid subtropical climate, with hot and muggy summers and cool to sometimes cold winters, rainfall is moderate and spread-out throughout the year. Bologna has a large walled old city containing mediaeval, renaissance and baroque buildings. Bologna has many art galleries and museums as well as hosting numerous festivals.