Susan Karike Huhume was a student in Papua New Guinea when she submitted the winning design for a new flag in 1971. Huhume incorporated the traditional Papua New Guinean tribal colors of red and black in the flag’s design, which is split diagonally. It features the Southern Cross constellation over a black background and a yellow bird-of-paradise (the country’s national bird) over a red background.

About one-third of the world’s countries feature religious symbols on their national flags. Christian symbols are found on the flags of 31 countries, but the only one of those countries to feature the Bible is the Dominican Republic. In the center of the national flag is the country’s coat of arms, which includes a cross, the branches of a palm and laurel, and the Bible.

Most flags look the same on the front and back, but three countries deviate from the norm. The Moldovan flag displays the coat of arms only on one side. The back of Paraguay’s flag shows the treasury seal. Saudi Arabia’s flag goes beyond being two-sided and instead sews two flags together because they show sacred writing.

After Muammar al-Qaddafi overthrew Egypt’s monarchy, he then changed Libya’s flag to an all-green look. When it flew from 1977 to 2011, it was the only plain-colored flag in the world. The move was meant to symbolize the “Green Revolution” that Qaddafi promised his citizens, a revolution that would bring water and other resources to make the desert fertile. The flag returned to the original striped design when Qaddafi was overthrown in 2011.

Introduced in 1848, the Irish flag represents the often fraught religious history of the country. It features three vertical color stripes: green, symbolizing Irish Catholics, and orange, representing Irish Protestants, which make up a much smaller percentage of the population. The stripe of white in the middle represents hope for lasting peace between the two.

The flag of Belize in Central America has 12 different colors, most of which are found on the coat of arms in the center of the flag, where you'll find several shades of browns, yellows, blues, and greens. The flag of Belize is also relatively new — it was adopted as the national flag in 1981 shortly after the country declared independence.

When Mexico achieved independence in 1821, the green, white, and red flag the nation adopted included a central emblem. Its likely inspiration was the myth of the Aztec city, Tenochtitlán (present-day Mexico City). A prophecy foretold an eagle with a snake in its beak standing on a cactus growing out of rocks in the middle of water.

At the 1936 Berlin Summer Olympics, Haiti and Liechtenstein discovered that their flags were identical. Haiti flew their civil flag that omitted the coat of arms found in the center of their national flag, which was reserved solely for military and government functions. The tiny European country of Liechtenstein coincidentally adopted the same red-and-blue striped pattern in 1921. The following year, they added a yellow crown to symbolize their prince and avoid any confusion in the future.

Surprisingly few national flags feature buildings, and only one features a UNESCO World Heritage Site. The flag of Cambodia depicts the Angkor Wat Temple in its center on a red band. The world’s largest religious structure, Angkor Wat is a sprawling Buddhist temple complex built in the early 12th century by King Suryavarman. It has been a UNESCO World Heritage Site since 1992.

Lebanon has been famous for its cedar trees since biblical times and remain a source of national pride. King Solomon was said to have procured wood from cedar trees to build the Temple in Jerusalem. In 1943, when Lebanon declared independence from France, the tree found a natural home on the country's national flag as well.

Red, white, and blue are so prevalent among national flags that only one country in the world, Jamaica, doesn’t feature any of those three colors on its national flag. The Jamaican flag consists of two black and two green triangles with a diagonal yellow cross separating them. The flag’s colors represent the sunshine of the nation (yellow), the hardship it’s faced (black), and the hope that lies ahead (green).

Nepal’s flag connects two pennant shapes, one atop the other, to symbolize the Himalayan Mountains. The top pennant bears a crescent with the sun rising over it, while the bottom half shows the image of the sun alone, both against a red background with a blue border. The sun and moon images signify Nepal’s hope that the country will last as long as those celestial bodies.

The flags of the Scandinavian countries use different colors and slightly different designs, but they all feature one thing in common: a Nordic cross. The cross — which is vertically oriented and stretched to all four corners of the flag — originated on banners that were once flown during war.

Spain's flag features three horizontal stripes. Emblazoned on the central yellow stripe is the nation's coat of arms with four quadrants that each contain a heraldic symbol. Representing the Kingdom of León is a lion. The symbol dates back to Roman times and is said to have been first used by a Roman legion in the first century CE.

The Union Jack is the national flag of the United Kingdom, but a different flag usually flies over Buckingham Palace: the Royal Standard, representing the U.K. sovereign. The Royal Standard follows the queen when she travels, so while she’s away from Buckingham Palace, the Union Jack flies in her absence.

Since 1625, Denmark has flown a flag bearing a white cross against a red field. However, a similar rendition of the flag has existed since as far back as the 1370s. Many other countries have used similar designs, with the white cross as a symbol of Christianity. In Denmark, the flag is called the “Dannebrog” or “Danish cloth.”

There are 195 different national flags in existence, representing the colorful countries and cultures of the world. The U.S. flag shares its colors — red, white, and blue — with 30 other countries, making it the most frequently used color combination in national flags. The majority of countries (nearly 40%) use three colors in their flag designs.

Brazil’s flag features 27 stars, second only to America’s 50-star flag. Unlike the U.S. flag, the stars on the Brazilian flag are scattered across a blue globe. The stars represent the 26 states and provinces in Brazil, along with the Federal District, with the size of each representing the size of each state’s territory.

In the “Land of the Rising Sun,” Japanese mythology tells the story of Amaterasu, the sun goddess from which the imperial family supposedly descended. Evidence of the use of a sun symbol on Japan’s flag dates back to the 12th century, but the current design — a simple red circle, representing the sun, on a white field — was adopted on August 5, 1854.

More than 30 countries today fly national flags in various patterns of red, white, and blue, but the first country to introduce this tricolor combination was the Netherlands. The Dutch flag was originally blue, white, and orange — to represent 16th-century William I, Prince of Orange, while fighting for Dutch independence against Spain. Around 1660, the orange transitioned to red, likely as a nod to the Dutch province of Zealand, which was branded with a red lion.

Only two countries’ flags have purple on them — Dominica and Nicaragua, both introduced in the late 19th century. For most of history, purple dye was far too expensive to use on flags, so artists opted for more affordable hues. Queen Elizabeth I once banned the use of purple outside the royal family, in order to control spending.