Stockholm Metro
The first thing you should visit in Stockholm, one of the most beautiful and interesting places, is, oddly enough, the metro. Here it is unique and unlike any other. Some stations are literally works of art.
When they were building the metro, instead of leveling the walls and laying ordinary tiles, they decided to decorate them with rock paintings. Each station is designed in its own style, so ride as much as possible and explore the most unique metro in the world.