From an isolated Pacific island with no running water to a spy base in England, these 5 places are practically out of sight for even the most curious traveler
The most fascinating things in life are often those that go beyond boundaries. And as travelers that means we're fascinated by places we're not allowed to visit.
Svalbard, Norway

Imagine a world forever changed by massive natural disasters. Earth's population destroyed, infrastructure destroyed, food resources destroyed. The mission of the survivor on Earth then is: Reconstruction. In such a Hollywood-inspired apocalyptic scenario, where does a hero go?

Enter the Svalbard greenhouse in Norway, humanity's last chance against a global food crisis. Located 120 m inside a sandstone mountain on the Norwegian island of Spitsbergen, 1,300 km from the North Pole, the Svalbard Greenhouse is the safest and most protected place for planting in the world.

Opened in 2008, this greenhouse protects Earth's crops against global catastrophe. With more than 250 million types of seeds from all over the world stored there, with the necessary tools, it offers seed samples that may be lost due to any incident, equipment failure or natural disaster.

There is a reason why scientists choose Spitsbergen: the island has never been shaken by tectonic activity and is 130 m above sea level, ensuring that the country will remain dry.
Nihau, Hawaii

Nihau, the smallest Hawaiian island, seems to be the ideal tropical escape, as it is home to abundant palm trees, endangered animals and virtually no tourists, but it is not. This is because this 180 square km island is out of the reach of visitors.
Sold by Hawaii's King Kamehameha in 1863 to the prominent Robinson family, who were wealthy plantation owners, the island has been off-limits since 1915. Life on the island is unusual: its nearly 130 permanent residents who they are of Hawaiian nationality, live rent-free, and manage without paved roads, telephone services, plumbing or stores. They use horses and bicycles for transport, provide electricity thanks to solar energy.

Children in Nihau take canoes to go to school. Although small, the island has played a historical role. It was on this very island that one of the Japanese fighter pilots that attacked Pearl Harbor crashed, terrorizing the residents. In 1944, the American President Franklin D. Roosevelt considered this island as a possible place for the construction of the headquarters of the United Nations.
British Air Force Menswith Hill, England

If James Bond had a secret bunker, this would be it. A military base in North Yorkshire, England, RAF Menwith Hill is believed to be the largest electronic monitoring station in the world. There they collect information about the United Kingdom and the United States. The secret base was built in 1954 to monitor the Soviet Union's communications during the Cold War.
No one knows for sure how the base is used today, but it is said to investigate international terrorist activity and drug trafficking, and act as a staging post for US satellites. It is also believed to have links to ECHELON, also known as the Five Eyes, the global spy network made up of Australia, Canada, New Zealand, the UK and the US.

There is no way to see inside the inner workings of this spy headquarters. The only people allowed in here are members of the NSA (National Security Agency) and ECHELON.
Secret Vatican Archives

Perhaps the most private library in the world, the Vatican Secret Archives is no ordinary library. It contains the personal documents of all the Popes dating back to the 8th century.
Closed to all non-Vatican staff since 1881, the archive keeps secret documents under lock and key, with a long and complex application process for those who want to see these secrets. Only qualified scholars can apply for admit cards. Applications should include personal information about the scholar, the purpose of his or her research, and a letter of introduction from a research institute in historical research. Even if a scholar is allowed to enter, the archives are numerous: there are about 85 km of drawers that hold over 35,000 volumes.

Among the historical treasures held in the archive are 14th century transcripts from the trial of the Knights Templar; correspondence from Michelangelo and Abraham Lincoln, and the Pope's call in 1198 for a Fourth Crusade to the Holy Land.
Area 51, Nevada

What happens in Vegas stays in Vegas. And the same can be said for a secret location about 80 miles to the north. Area 51, a term first used in a CIA document during the Vietnam War, is a military and air base that is known to hold many state secrets.
What happens there? The CIA won't give details, which is why it's full of conspiracy theories. All activities in Area 51 are considered secret and access is strictly prohibited to outsiders. Although many people try./ BBC