Warsaw - Istambul

Have we just arrived in Istambul?

Are we looking at a mosaic art piece? so many of them in the underground passages of Istambul...

No, we aren't! we are in Warsaw. Waters of Bosfor mix with those of Vistula river:

This mosiac is located at Metro Politechnika, in the southern passage. It was founded by the Turkish government in 2014 in order to celebrate the 600th anniversary of Polish-Turkish official relations.