Udisha
Poveglia Island, Italy
Located in Italy's Venice, Poveglia Island was used as a quarantine station back in the day. The island, now abandoned, was used to ship patients during outbreak of plagues. The island has never been open to tourists due to safety reasons.
Area 51
A US military site in a desert in Nevada, Area 51 is used to test aircrafts and other military equipments. Protected with high security, you will have to pay a hefty fine if you dare trespass.
Tomb of Qin Shi Huang
In the tomb of Qin Shi Huang, lies the underground palace of the first ever emperor. This place is legally banned for tourists and is full of mechanical traps to keep people away from the historic site.
Chernobyl's Elephant Foot
After the 1986 disaster at the Chernobyl Nuclear Power Plant, near Pripyat, Ukraine, a corium deposit in the shape of an elephant's foot had formed beneath the Reactor 4, making it highly poisonous. Quite naturally, the place is off-limits because it continues to pose lethal health threats.
Gangkhar Puensum
Situated in the Bhutan-China border, the 7570 m Gangkhar Puensum peak is the world's highest unclimbed mountain. This is because Bhutan has banned climbing peaks higher than 6,000m because they are believed to be sacred.