> Paris is very complicated underground. Besides the quarries there are the sewers, catacombs, some underground lakes, reservoirs, etc. It is definitely a complicating factor when planning new metro tunnels.
I wonder if the French are considering digging underneath all those obstacles? Seems to be the way London has gone with the Elizabeth Line. Although that may still be shallower than Paris' quarries and lakes.
I wonder if the French are considering digging underneath all those obstacles? Seems to be the way London has gone with the Elizabeth Line. Although that may still be shallower than Paris' quarries and lakes.