Sister Cities, also known as twin towns, are long-term partnership between two communities from two countries, where cultural, technical, educational and business exchanges are made.

They’re friendship is cemented by either town’s mayors (or highest elected official) sign a memorandum establishing the relationship.

The United States in total shares 200 sister relations with China. Oakland, California alone has 17 Sister Cities in China. Beijing, China’s capital, shares sisterhood with Washington, D.C. and New York City.

Take a look at the Chinese and US Sister Cities

Chicago is Shanghai’s Sister City and both are known for their extensive metro systems.
Beijing is a Sister City with New York City.
Along with Beijing, Washington D.C. is a Sister City with Chongqing.