Unusual among European cities Athens does not have a river that flows freely through the city. In the 1930’s during rapid urban development the Ilissos River was covered over and a tram line built on top of it.
In October 2018 the tram line closed after poor maintenance and the rumble of thousands of trams caused the tunnel to collapse. Planners have suggested that instead of spending many millions of euros repairing the tunnel, the tram line should be diverted along a different route and the river opened up. They have proposed that a park alongside a mile long stretch of the river be created. Athens city centre has few parks and gardens and the city was ranked 22ndout of 30 cities in a European Green City Index. (London was 11th.)
In ancient times the Ilissos River was, according to Socrates, an idyllic, winding watercourse shaded by plane trees.