Dortmund ([ˈdɔɐ̯tmʊnt] ( listen); Low German: Düörpm; Latin: Tremonia) is a city in Germany. It is located in the Bundesland of North Rhine-Westphalia. Its population of 579,012 (in December 2012) makes it the 8th largest city in Germany. Dortmund is the largest city in the Ruhr Area, an urban area with some 5.2 million (2009) inhabitants which is the largest urban agglomeration in Germany. Dortmund is also a part of the larger Rhine-Ruhr metropolitan region of more than 12 million people.
The river Ruhr flows south of the city, and the small river Emscher flows through the municipal area. The Dortmund-Ems Canal also terminates in the Dortmund Port, which is the largest European canal port, and links Dortmund to the North Sea.
Dortmund is known as Westphalia's "green metropolis". Nearly half the municipal territory consists of waterways, woodland, agriculture and green spaces with spacious parks such as Westfalenpark and the Rombergpark. This contrasts with nearly a hundred years of extensive coal mining and steel milling within the city limits.
Opera houses are listed by continent, then by country with the name of the opera house and city; the opera company is sometimes named for clarity.
Note: there are many theatres whose name includes the words Opera House but which do not currently put on opera regularly (or, in some cases, at all). Such theatres are not included in this list.
However, in some cases, articles exist for historically important houses which no longer present opera or which may have been destroyed. These articles will remain on this list.