Europe InterRail Map
You can visit up to 30 different Countries in Europe using the global pass for Inter Rail. Or if you prefer to you can visit any of the 27 Counties using the InterRail One Country Pass.
The reason why the InterRail One Country Pass is only vaild in 27 counties is because for visits to the Belgium, The Netherlands and Luxembourg you will have to purchase a different pass, the InterRail Benelux Pass which allows travel to the three countries in one.
Another option you can have is the Greece Plus Pass if visiting Greece, this pass alows you to travel on ferry to Italy, which can be useful to those wishing to experience another country for a day.