Thanks to technology, the world is virtually accessible to everyone. If you have the money, you can take a plane and get to most destinations in the world under 24 hours.
That's why it's fascinating to think about how even the wealthiest couldn't (or shouldn't) go to certain locations. You have to be in-the-know, a head of state, a priest, or a native member of a tribe that hasn't had contact with the modern world (don't worry, you'll see in the list).
From top secret government locations to sacred spaces to radioactive cities lost to time, these are the most travel-restricted places in the world.