The most tempting things in life are often those that are forbidden. For travelers, this sparks most interest and fascination on the places they are not allowed to visit.

Svalbard Global Seed Vault, Norway

Svalbard Global Seed Vault is located 120m inclusive in a sandstone mountain on the Norwegian island of Spitsbergen. The place is1,300km from the North Pole, in the remote Arctic Svalbard archipelago. The Svalbard Global Seed Vault is the utmost secured, strongly guarded seed bank in the world.

It opened in February 2008; Express reported that the vault contains Earth's crops against global cataclysm events. It has 250 million crop seeds from around the world packed in specially designed four-ply packets and heat-sealed to protect against moisture. The vault provides samples of seeds that may be lost due to equipment failures, accident, natural disasters, and funding cuts. Unless you are a titled researcher or plant breeder, you are not allowed to even just visit not get inside the vault.

Ni'ihau, Hawaii

Ni'ihau, the smallest populated Hawaiian island. This 180sqkm Pacific island is off-limits to outsiders. The island has banned outsiders since 1915. The island has 130 permanent residents, who are Native Hawaiians, living rent-free, without concreted roads, plumbing, running water or stores, and telephone services.

Horses and bicycles serve as their transportation, solar power is the source of their electricity and barges brings groceries from neighboring Kaua'i. The island remains off-limits today, the Coast Guard guards the island to guarantee that no landings are attempted. No one is allowed to visit without an invitation from someone living on the island.

Vatican Secret Archives, Vatican

The Vatican Secret Archives is possibly the most reserved library in the world. It encloses the personal documents of all the popes from the 8th century up to the present. Since 1881, the place was closed to all non-Vatican figures. According to BBC, the archive preserves top-secret documents under a long and intricate application process for those who want to access its secrets.