Reggio Emilia also referred to by its more official name of Reggio nell'Emilia or colloquially Reggio by its inhabitants, is a city in northern Italy, in the Emilia-Romagna region. It has about 171,944 inhabitants and is the main comune (municipality) of the Province of Reggio Emilia. The inhabitants of Reggio nell'Emilia are called Reggiani, while the inhabitants of Reggio di Calabria are called Reggini. The old town has a hexagonal form, which derives from the ancient walls, and the main buildings are from the 16th–17th centuries. The comune's territory is totally on a plain, crossed by the Crostolo stream.