Being in Paris, it’s hard to pass its metro, all the more the city is just laced with lines of the underground transport. Paris metro is the most “dense” in the world and the third oldest in Europe after only London and Budapest. The first station of Paris Metro (along with many other objects, created for Paris World Exhibition) was opened in 1900.
Metro in Paris is initially shallow and the first lines were laid directly under the city streets because the deviation from the “route” could lead builders to someone’s cellar or basement. Major part of the lines in the city center was started already before 1920-th years. And their distinctive feature was a small stretch between underground stops, a large number of stations, made in modern-style (the author of the design of many stations – Hector Guimard).