Tokyo, Japan
The subway system in Tokyo is massive but is very easy to use, in my opinion. There are actually 2 grids and I am only using the JR one which is quite comprehensive and gets me to wherever I need to go. All the stations and trains have very clear Japanese and English signage. They also allocate an alphabet and number to each station so it is even easier to use than the London one. Other cities could learn a few lessons from the Japanese! So for example, if you we...