Dugway

Dugway
Very much like the Marshall Islands, Dugway was also part of a weapon test site, which was known as the Dugway Proving Ground. But in place of nuclear weapons, the nature of this test site is more threatening, biological and chemical forces. In the meantime, they produce procedures to counter their effects. Located in Utah, Dugway is a place you certainly cannot visit.
Heard Island Volcano

Heard Island Volcano
An outermost territory of Australia that lies between Madagascar and Antarctica, Heard Island is about 1,700 km from the Antarctic continent. It includes Australia’s tallest mountain, with an active volcano. Now you understand why it is off-limits? However, aside from the possible risk of the volcanoes and the natural habitat, this is also why Heard Island is forbidden.