A passport is the key to getting into other countries. You might have noticed, maybe while waiting in the passport-control queue, that these travel documents come in only a few colours. In general, passports are only red, green, blue, or black. Passports do, however, come in different shades of each of the four main colour groups.
Here's what each colour is - and what each one means
RED
Burgundy passports are used by members of the European Union (sans Croatia), and countries interested in joining (think: Turkey) have changed their passport colors to match. The Andean Community (also known for past EU-ambitions) of Bolivia, Colombia, Ecuador, and Peru also has burgundy passports. The Swiss passport, in effortless and famously Swiss-fashion, matches their flag.
BLUE
In second place is the colour blue, reports Travel and Leisure.
Blue reportedly symbolizes "the new world" with 15 of the Caribbean countries opting for it.
Further south down the South American continent, Brazil, Argentina and Paraguay also use a blue passport – the cover symbolising the connection with the Mercosur trade union.
The most famous blue passport in the world though has to be the one issued to US citizens – but this was changed to blue as recently in 1976.
GREEN
Most Islamic countries use green passports as it was believed to have been a favourite colour of the Prophet Muhammad, and is considered to be a symbol of nature and life.
Examples are Morocco, Saudi Arabia, and Pakistan.
Variations of green are also used by members of ECOWAS - Economic Community of West African StateS - including Niger and Senegal.
BLACK
The reason for the least common passport colour may be rooted in practicality - as may all of them in fact. The dark colours chosen obviously don't show up dirt as much, and they look nicely official. The Republic of Botswana, Zambia and New Zealand issue band passports, though it should be noted black is New Zealand's national colour.