You can tell a lot about a country from its passport. Color is the first give-away. Nations tend to pick colors that reflect their national character. New Zealand decorates its famous rugby team, its airline and its passports in the nation's favorite color—black. Many Islamic countries have green passports because of the importance of the color in the Muslim faith.

    But as well as a statement of national identity, color can show international cooperation. The British passport was originally a navy blue. But after Britain joined the European Union in 1973, it switched to burgundy red（酒红色）like other EU countries. The common color was supposed to make European passports instantly recognizable.

    But since colors can't be patented（专利）, nothing stops others with the same idea. A number of countries that long to join the EU have changed their passports to burgundy too. Meanwhile Britain has decided to leave the club. Its government has announced that the UK passports will return to navy blue after Breit（脱欧）.

    If you have a passport from Singapore or South Korea, you are in possession of one of the most powe3rful travel documents on earth. Passport power is measured by the number of countries the holder can access visa-free. Currently sharing first place in the power rankings, Singaporean and South Korean passports provide visa-free access to 162 countries each. British passport holders share fourth place in the power ranking with six other nations, each accessing 159 countries visa-free. Americans ranked fifth with access to 158. Somalia, Syria, Pakistan and Iraq are among the world's least powerful passports. Afghanistan is the lowest ranking of all, with visa0free access to just 26 countries.

    Having to get a visa is not a piece of cake. First there is the never-ending form. Then there are lengthy appointments and expensive fees. Some visas also require travelers to pre-booked flights to prove that they intend to return home.

    But there are unexpected advantages to some of the world's weaker passports. Middle-ranking Namibia is one of just a handful of countries, whose citizens can enter Angola visa-free. India is one of only three countries, whose citizens have visa-free access to Bhutan.

    A low-ranking passport limits your choices, but not your sense of adventure.