No issue no need to have wall, there should be wall on theory though.
Most borders in the world use natural barriers. This is called natural border, such as the top spot of Mount Everest is the border between Nepal and China.
No issue no need to have wall, there should be wall on theory though.
Most borders in the world use natural barriers. This is called natural border, such as the top spot of Mount Everest is the border between Nepal and China.