Looking to take a dip in or near a city center? Here are some urban areas that have successfully opened up waterways for swimmers.The Olympic Games in Paris generated a lot of excitement around the cleanup project of the Seine River, where triathlon and swimming competitions took place. And there’s more to come: Mayor Anne Hidalgo plans to open three public swimming spots on the Seine by next summer, and similar projects are in the works in Boston, London and Amsterdam.But these plans to develop “blue infrastructure” — which can help cool cities, promote biodiversity and improve quality of life — won’t be the first. Here are six European cities that have successfully opened up their waterways for swimming.ParisDip into floating swimming pools filled with filtered canal water.Freshwater pools at the Bassin de la Villette, a large artificial lake at the northeastern edge of Paris.Dmitry Kostyukov for The New York TimesSome Parisians can still remember a time when the banks of the Seine were lined with floating swimming pools — with views of the Pont Neuf and the National Assembly. (The Piscine Deligny was built on a floating barge in the Seine in the late 1700s; it sank in 1993.)We are having trouble retrieving the article content.Please enable JavaScript in your browser settings.Thank you for your patience while we verify access. If you are in Reader mode please exit and log into your Times account, or subscribe for all of The Times.Thank you for your patience while we verify access.Already a subscriber? Log in.Want all of The Times? Subscribe.