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Gangdiguo is a metropolitan city and district in the Jingdaoese province of Zhongji. Before 1659 AN, the city of Heliopolis was located here, but with major construction works on orders of the Chidao Emperor, the current landscape and city came into existence. With over 40 million inhabitants on a small surface area, the city is the most densely populated in the empire. Most of the citizens are employed in the enormous industrial and logistics sectors. The city is the economic capital of the Gangdiguo Special Economic Zone, a designated area in Jingdao where USSO citizens can settle and trade. All USSO citizens living in Jingdao are considered to be de jure inhabitants of Gangdiguo.
The city is well-known for its small apartments for workers which consist of only bedrooms and a bathroom. Kitchens and living rooms are rare. Most of the workers eat and socialize in their working place, which also takes full care for their children.