Which countries do not allow immigration?

Which countries do not allow immigration?
Here are some of the most challenging countries to immigrate to:

Saudi Arabia.
Kuwait.
Bhutan.
China.
Japan.
Switzerland.
Denmark.
Liechtenstein.

Here are some of the most challenging countries to immigrate to:
  • Saudi Arabia.
  • Kuwait.
  • Bhutan.
  • China.
  • Japan.
  • Switzerland.
  • Denmark.
  • Liechtenstein.
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