--祖冲之--

The Han Dynasty lasted for 427 years from 206 BC to 220 AD. When it fell, the Three Kingdoms period took its place as local power centers established their own dynasties. They were reunited to form the Jin Dynasty (晋 264 to 420) which lasted 157 years in various forms. The Jin Dynasty was under constant attack from the north as the Xiongnu culture of the northern plains moved south followed by the Jie and the Xianbei. Each were distinct cultures that brought not only war and destruction but new ideas and practices.
~ During and after the Jin Dynasty there was a massive movement of population to the south of the Yangtse River for safety. The Jin Dynasty broke up into small kingdoms. This is called the Sixteen Kingdoms period (五 胡 十 六 国 (304 to 439) and overlaps the establishment of the five Northern and four Southern Dynasties (南 北 朝 386 to 589). The Southern Dynasties had their capitals south of the Yangtse River in Nanjing. The four Southern Dynasties were: Liú-Sòng 刘宋 420-479, Southern Qí 南齐 479-502, Liáng 南梁 502-557, and Chén 南陳 557-589.
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~http://hua.umf.maine.edu/China/astronomy/tianpage/0014ZuChongzhi9296bw.html
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--Amsterdam--

Amsterdam (pronounced /ˈæmstərdæm/; Dutch [ˌɑmstərˈdɑm] ( listen)) is the capital and largest city of the Netherlands, with an urban population of 1,364,422 and a metropolitan population of 2,158,372.^{[citation needed]} The city is in the province of North Holland in the west of the country. It comprises the northern part of the Randstad, the sixth-largest metropolitan area in Europe, with a population of approximately 8.1 million.
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Its name is derived from Amstellerdam, indicative of the city's origin: a dam in the river Amstel. Settled as a small fishing village in the late 12th century, Amsterdam became one of the most important ports in the world during the Dutch Golden Age, a result of its innovative developments in trade. During that time, the city was the leading centre for finance and diamonds. In the 19th and 20th centuries, the city expanded, and many new neighbourhoods and suburbs were formed. The 17th-century canals of Amsterdam (in Dutch: 'Grachtengordel'), located in the heart of Amsterdam, were added to the UNESCO World Heritage List in July 2010.
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~http://en.wikipedia.org/wiki/Amsterdam