Have you ever thought about going from London to Paris riding the tube? How long are the underground veins that run below major cities in Europe? With this visualization we compare the total length and fares of the different subway systems across the continent, revealing interesting insights and confronting the actual sizes on the map. Download the english translation of the visualization at this link: http://www.accurat.it/files/corriere/03_european_subterranean_veins.pdf