To some people, passports are treasured and hard-won documents that represent their nationality and open the door to explore the world; to others, they are a barrier of movement for citizens of the world. Here are some fascinating facts about passports that will make you appreciate them in a whole new way.

1. China's new passport holds secret sceneries

Holders of Chinese passports issued after May 2012 are able to witness the secret scenery hidden inside under UV light. Each page of the passport is decorated with famous tourist attractions across China, when displayed under UV light. 

2. The first passport was in the Bible

Rather than functioning as a document that determines whether a person could leave his country, passports in the old days were requests from one king to another soliciting safe passage for the individual in passing through foreign territory.

In the book of Nehemiah of the Bible, King Artaxerxes I of Persia gave a letter to an official Nehemiah granting him safe passage on his travels through Judea. Nehemiah who then became the first passport-holder in the world.

3. Photographs for passports were only needed after the First World War

Early passports had no photographs. Photographs were only required after the start of the First World War after a Germany spy entered Britain with a fake U.S. passport.

4. The Nicaraguan passport is the least forgeable

The Nicaraguan passport boasts 89 separate security features, including "bi-dimensional barcodes," holograms and watermarks, and is regarded to be one of the least forgeable documents in the world.

5. The Vatican has no passport control

Vatican is the smallest country in the world, a walled enclave located within Rome in Italy. The Vatican has no passport control. If you can enter Italy, you can enter Vatican. But it does issue passports. The Pope, among his other honors, always carries "Passport No. 1".

6. Tonga sells passports

The late King of Taufa'ahau Tupou IV of Tonga reportedly sold Tongan passports to non-citizens for 20,000 U.S. dollars to raise the countries revenue.

7. Finnish and Slovenian passports act like flicker-books

The Finnish passport features an elk on the bottom of each page and bored travelers will see the animal amble across the document if flipping them rapidly. A similar effect is seen on the Slovenian passport.

8. Family photos were acceptable in a passport

When the British government introduced passport photographs in February 1915, the whole families could be shown in the photograph. As long as faces were visible, the pose and location of those involved did not matter.

9. The Queen of the UK does not have a passport

As the Queen of the UK is the one granting permission to all the UK passports, she doesn't actually need one herself for traveling abroad, but the rest of the Royal Family do.

10. The Northern Lights is hidden in Scandinavian passports

If you shine a Scandinavian passport under UV light, the aurora borealis will appear as iridescent trails on the paper, which is an innovative approach to security, making it the coolest passport in the world.