Information:  - A corporation is a company or group of people authorized to act as a single entity (legally a person) and recognized as such in law. Early incorporated entities were established by charter (i.e. by an "ad hoc" act granted by a monarch or passed by a parliament or legislature). Most jurisdictions now allow the creation of new corporations through registration.  - North Rhine-Westphalia (, commonly shortened to NRW) is the most populous state of Germany, with a population of approximately 18 million, and the fourth largest by area. Its capital is Düsseldorf; the most populous city is Cologne. Four of Germany's ten largest citiesCologne, Düsseldorf, Dortmund, and Essenare located within the state, as well as the largest metropolitan area on the European continent, Rhine-Ruhr.  - Germany, officially the Federal Republic of Germany, is a federal parliamentary republic in central-western Europe. It includes 16 constituent states, covers an area of , and has a largely temperate seasonal climate. With about 82 million inhabitants, Germany is the most populous member state of the European Union. After the United States, it is the second most popular immigration destination in the world. Germany's capital and largest metropolis is Berlin. Other major cities include Hamburg, Munich, Cologne, Frankfurt, Stuttgart and Düsseldorf.  - Coal is a combustible black or brownish-black sedimentary rock usually occurring in rock strata in layers or veins called coal beds or coal seams. The harder forms, such as anthracite coal, can be regarded as metamorphic rock because of later exposure to elevated temperature and pressure. Coal is composed primarily of carbon, along with variable quantities of other elements, chiefly hydrogen, sulfur, oxygen, and nitrogen. A fossil fuel, coal forms when dead plant matter is converted into peat, which in turn is converted into lignite, then sub-bituminous coal, after that bituminous coal, and lastly anthracite. This involves biological and geological processes that take place over time.  - South Africa, officially the Republic of South Africa (RSA), is the southernmost country in Africa. It is bounded on the south by of coastline of Southern Africa stretching along the South Atlantic and Indian Oceans, on the north by the neighbouring countries of Namibia, Botswana and Zimbabwe, and on the east and northeast by Mozambique and Swaziland, and surrounding the kingdom of Lesotho. South Africa is the 25th-largest country in the world by land area, and with close to 56 million people, is the world's 24th-most populous nation. It is the southernmost country on the mainland of the Old World or the Eastern Hemisphere. It is the only country that borders both the Atlantic Ocean and the Indian Ocean. About 80 percent of South Africans are of Sub-Saharan African ancestry, divided among a variety of ethnic groups speaking different Bantu languages, nine of which have official status. The remaining population consists of Africa's largest communities of European (white), Asian (Indian), and multiracial (coloured) ancestry.  - The Rhine (, , ) is a European river that begins in the Swiss canton of Graubünden in the southeastern Swiss Alps, forms part of the  Swiss-Austrian, Swiss-Liechtenstein, Swiss-German and then the Franco-German border, then flows through the Rhineland and eventually empties into the North Sea in the Netherlands.  The largest city on the river Rhine is Cologne, Germany, with a population of more than 1,050,000 people. It is the second-longest river in Central and Western Europe (after the Danube), at about , with an average discharge of about .  - The Ruhr, or the Ruhr district, Ruhr region, Ruhr area or Ruhr valley, is a polycentric urban area in North Rhine-Westphalia, Germany. With a population density of 2,800/km² and a population of eight and a half million, it is the largest urban agglomeration in Germany, and third-largest in the European Union. It consists of several large, industrial cities bordered by the rivers Ruhr to the south, Rhine to the west, and Lippe to the north. In the southwest it borders the Bergisches Land. It is considered part of the larger Rhine-Ruhr metropolitan region of more than 12 million people, which is among the largest in Europe.  - The Rhine-Ruhr metropolitan region is the largest metropolitan region in Germany with over 11 million inhabitants. It is of polycentric nature and the only megacity in Germany. It covers an area of 7,110 square kilometers and lies entirely within the federal state of North Rhine-Westphalia. The Rhine-Ruhr metropolitan region spreads from Dortmund-Bochum-Essen-Duisburg (Ruhr Area) in the north, to the urban areas of the cities of Mönchengladbach, Düsseldorf (the state capital), Wuppertal, Leverkusen, Cologne (the region's largest and Germany's fourth largest city), and Bonn in the south. The location of the Rhine-Ruhr at the heart of the European blue banana makes it well connected to other major European cities and metropolitan areas like the Randstad, the Flemish Diamond and the Frankfurt Rhine Main Region.  - The Bergisches Land ("Country of Berg" or "Land of Berg", 'Berg' meaning mountain) is a low mountain range region within the state of North Rhine-Westphalia, Germany, east of Rhine river, south of the Ruhr. The landscape is shaped by woods, meadows, rivers and creeks and contains over 20 artificial lakes. Wuppertal is the biggest town and seen as the region's capital, whereas the southern part nowadays has closer economic and socio-cultural ties to Cologne. Wuppertal and the neighbor cities of Remscheid, Solingen form the Bergisches Städtedreieck.  - Coal mining is the process of extracting coal from the ground. Coal is valued for its energy content, and, since the 1880s, has been widely used to generate electricity. Steel and cement industries use coal as a fuel for extraction of iron from iron ore and for cement production. In the United Kingdom and South Africa, a coal mine and its structures are a colliery. In Australia, "colliery" generally refers to an underground coal mine. In the United States "colliery" has historically been used to describe a coal mine operation, but the word today is not commonly used.  - A Company is a legal entity made up of an association of persons, be they natural, legal, or a mixture of both, for carrying on a commercial or industrial enterprise. Company members share a common purpose and unite in order to focus their various talents and organize their collectively available skills or resources to achieve specific, declared goals. Companies take various forms such as:  - In the study of human settlements, an urban agglomeration is an extended city or town area comprising the built-up area of a central place ("usually a municipality") and any suburbs linked by continuous urban area. INSEE, the French Statistical Institute, uses the term "unité urbaine", which means continuous urbanized area. However, because of differences in definitions of what does and does not constitute an "agglomeration", as well as variations and limitations in statistical or geographical methodology, it can be problematic to compare different agglomerations around the world. It may not be clear, for instance, whether an area should be considered to be a satellite and part of an agglomeration, or a distinct entity in itself.  - The European Union (EU) is a political and economic union of member states that are located primarily in Europe. It has an area of , and an estimated population of over 510 million. The EU has developed an internal single market through a standardised system of laws that apply in all member states. EU policies aim to ensure the free movement of people, goods, services, and capital within the internal market, enact legislation in justice and home affairs, and maintain common policies on trade, agriculture, fisheries, and regional development. Within the Schengen Area, passport controls have been abolished. A monetary union was established in 1999 and came into full force in 2002, and is composed of 19 EU member states which use the euro currency.  - Australia, officially the Commonwealth of Australia, is a country comprising the mainland of the Australian continent, the island of Tasmania and numerous smaller islands. It is the world's sixth-largest country by total area. The neighbouring countries are Papua New Guinea, Indonesia and East Timor to the north; the Solomon Islands and Vanuatu to the north-east; and New Zealand to the south-east. Australia's capital is Canberra, and its largest urban area is Sydney.  - Westphalia is a region in northwestern Germany and one of the three historic parts of the state of North Rhine-Westphalia. It has an area of 7,802 sq mi (20,208 km²) and 7.9 million inhabitants.  - RAG AG , formerly Ruhrkohle AG , is the largest German coal mining corporation . The company headquarters are in Herne in the Ruhr area . The company was founded on 27 November 1968 , consolidating several coalmining corporations into the Ruhrkohle AG. On 12 September 2007 as a result of restructuring , the business areas of chemicals , energy and real estate were transferred to the new business entity Evonik Industries AG. Evonik Industries are headed by the RAG - Stiftung ( English : RAG - Foundation ) , which uses corporate profits to finance the costs that arise due to the former mining activities in the Ruhr region .  - The United Kingdom of Great Britain and Northern Ireland, commonly known as the United Kingdom (UK) or Britain, is a sovereign country in western Europe. Lying off the north-western coast of the European mainland, it includes the island of Great Britain (the name of which is also loosely applied to the whole country), the north-eastern part of the island of Ireland, and many smaller islands. Northern Ireland is the only part of the UK that shares a land border with another sovereign statethe Republic of Ireland. Apart from this land border, the UK is surrounded by the Atlantic Ocean, with the North Sea to its east, the English Channel to its south and the Celtic Sea to its south-south-west, giving it the 12th-longest coastline in the world. The Irish Sea lies between Great Britain and Ireland. With an area of , the UK is the 78th-largest sovereign state in the world and the 11th-largest in Europe. It is also the 21st-most populous country, with an estimated 65.1 million inhabitants. Together, this makes it the fourth most densely populated country in the European Union.    What entity does 'rag ag' has the relation 'headquarters location' with?
Answer:
essen