Bologna became a commune by 1114, but it desired independence and in 1176 it joined the Lombard League, an alliance opposed to the Holy Roman Empire's influence.

Worthy of note for its particularity is the Dardagna torrent, the only river in the territory of the metropolitan city which, flowing into the Panaro, is part of the Po water basin.

In the extensive hill system, two ridges stand out which are located transversally to the main valleys: the Pliocene Buttress and the Chalk Vein.

Characteristic are the gullies, hilly formations dug by the flow of rain on the clayey slopes of different densities, present along the Chalk Vein on the hills from Reggio nell'Emilia to the province of Rimini.

Inside the Metropolitan city of Bologna are present 5 Regional Parks (Corno alle Scale, Gessi Bolognesi and Calanchi dell'Abbadessa, Monte Sole, Monteveglio Abbey, Suviana and Brasimone Lake), 2 Provincial Parks (Montovolo, La Martina), 1 Nature Reserve (Countrafforte Nature Reserve Pliocene), 13 Ecological Rebalancing Areas (ARE).

The driving sectors of the regional economy are: agriculture (vegetables, cereals – the famous DOP potato from Budrio), breeding (pigs and cattle) and small and medium industry in the food, mechanical, ceramic and electronics.

Among the highly relevant agri-food industries in Bologna we find: in the food sector Granarolo, Fabbri, Segafredo Zanetti, Montenegro, Valsoia, the Conserve Italia consortium (to which the Cirio, Yoga, Valfrutta, Derby Blue and Jolly Colombani), Eridania, Alcisa, Cremino maker Majani, Carpigiani, Cerelia Acqua Minerale, as well as the national offices of the food cooperatives Coop (Italy), Conad and Sigma, SISA and Despar.

In recent years, numerous start-ups in the field of information and communication technologies have been created in the Emilian capital.