Bizarre facts you never knew about the world's passports

At just 125mm long and barely 90mm wide, a passport is one of the world's most important documents even though it comes with less than 40 pages.

It not only allows the owner to travel across international borders but it also serves as an official identification document.

But just how much do we know about this little book which is used and desired by billions of people around the world?

Sweden's passport is the most powerful in the world, according to travel site GoEuro, and it is also one of the most highly sought-after travel documents in the black market.

It can cost up to 6,000 pounds (S$12,500) for one, compared to the 28 pounds fee to make or renew it in Sweden.

If you are wondering, the costliest passport to produce is in Turkey - at a price of 166 pounds.

Passports also come with many features, including some which can be hidden between the pages.

Malaysia was the first country to issue biometric passports and Austrians are allowed to have two copies of their passport to circumvent certain travel restrictions.