Chicago has 28 Sister Cities. Like Chicago, many of them are or were, the second city of their country, or they are the main city of a country that has had many immigrants settle in Chicago. Paris is a Partner City, due to the one sister city policy of their respective French commune.
To celebrate the sister cities, Chicago hosts a yearly festival in Daley Plaza, which features cultural acts and food tastings from the other cities. In addition, the Chicago Sister Cities program hosts a number of delegation and formal exchanges. In some cases, these exchanges have led to further informal collaborations, such as the academic relationship between the Buehler Center on Aging, Health & Society at the Feinberg School of Medicine of Northwestern University and the Institute of Gerontology of Ukraine (originally of the Soviet Union), that was originally established as part of the Chicago-Kyiv sister cities program.