Passports help travellers get from A to B but they can look very different depending on what country they are issued in.
In India, for example, the travel books are a bold blue colour, but those who live in Europe will be more familiar with the burgundy design - and these hues are decided individually by each country.
Although countries have the freedom to determine their own shade, in the past it hasn't always been an easy decision.
It took nine members of the-then European Community (now the 28-strong EU) years to finally adopt the red shades its countries use now.
Croatia is the only exception with a blue cover.
Interestingly the EU passport was almost a lilac colour, with diplomats dismissing maroon as being mundane, according to reports at the time.
The red design was begrudgingly chosen in 1981, with Britons said to be unhappy at the presumed French influence in the decision.
In September 1988, Glasgow Passport Office issued the first UK passports in the European Commission common format, and this was extended to other offices by the spring of 1991.
The continuity of passport colour in the EU was supposed to make them instantly recognisable, although it also attracted colour adoptions of other EU-hopefuls.
According to the Economist, in South America the Andean Community, which once had EU-like aspirations, also favours wine-coloured passports.
There are a number of similar groupings by colour, such as the four of the CA-4 Treaty (El Salvador, Honduras, Guatemala and Nicaragua).
Their common designs, known as the Central American passport, are navy blue in colour.
Claire Burrows of De La Rue, a British company that has been making passports since 1915, said that countries can choose colours that reflect their nation.
Switzerland, for example, has a bright red passport cover, mirroring its bold flag.
Similarly many Islamic countries adopt a green cover, which features in many of their flags.
And usually Communist nations, or nations that were formerly under the Communist regime, use red-coloured passports.
Practicality may play a part in colours chosen to represent a country, according to Bill Waldron of Holliston, a Tennessee-based firm that prints documents for 63 of the world's passport-issuing countries.
Waldron said that darker colours show less dirt, heighten the contrast with the crest and look more official.
The colour differences get more complicated when varying ones are also used within countries to denote a particular status.
In the United States, most people own a dark blue passport, but maroon or dark red passports may be seen at airports for those travelling on official US government business or by some US military and their families.
Less common are the black passports used for diplomatic business and special-edition green-coloured ones which were created to mark the 200-year anniversary of the US Consular Service.
And while colours help to distinguish different nations, some are more powerful than others.
Even if you are lucky enough to have access to the government-issued documents, you are still restricted where you can travel to, with certain passports.
The Passport Index lists which countries have the greatest access visa-free to places round the world, with the United Kingdom and the United States enjoying the greatest freedom.
Travellers from both nations are able to visit 147 countries using their passports, followed by South Korea, Germany and France on 145.