We’ve all heard of national holidays, perhaps even independence day celebrations, depending on the country. Some of us know the dates on the calendar; July 4th in the USA, May 17th in Norway, February 11th in Iran. And even lesser known important dates for countries, like Ohi Day on October 28th in Greece. Of course, there are also days of remembrance, such as November 11th in the US, France, and UK. But what about holidays that only parts of countries celebrate?

We’ve all heard of the long-reigning cultures of the Chinese, the Mayan, or the Vikings. And some of us have heard of the Abyssinians in east Africa, or the Pandyan of the ancient state of Tamil in South India. But did you know there’s another culture, still in existence, that outlasts all these cultures combined?

We’ve all heard of languages like Latin or Greek, that provide the basis for well-known language families. And some of us have heard that languages like Icelandic and Tamil have been in use for centuries with little alteration. But do you know about a language that uses its own alphabet that is different from any other in the world, and is just as old as Celtic?

We’ve all heard of the wonders of the ancient world; the statue of Zeus at Olympia, the Library of Alexandria, or the Great Pyramids of Egypt. At least that one’s still with us. And some of us have heard of historic African rulers like King Tut or Pharaoh Ramses the Great. But do you know who was actually the most prolific builder in ancient Africa?

We’ve all heard of treaties between countries; to end wars, agree to trade, or build alliances. And some of us have heard of specific treaties, like the Treaty of Versailles at the end of World War One, or the Geneva Conventions that established a standard for humanitarian conduct during war. But how many of us have heard of a treaty of governance that multiple countries signed? The countries being Argentina, Australia, Belgium, Chile, France, Japan, New Zealand, Norway, Russia, South Africa, the United Kingdom, and the United States.

We’ve all heard of Jerusalem and the centuries-long history of its religious importance. Some of us have heard of other holy cities of the world, like Mecca, Varanasi, and Rome. Even some more ancient ones like Bethlehem, Corinth, and Fes. And yet, there is another religious center, of Christianity in particular, that is just as old and still relevant today.

We’ve all heard of the Roman Empire - apparently, men think about it more often than we thought. And some of us have heard of other empires like the Spanish, French, British, and Russian. Even some less obvious ones like the Mayan, Persian, and Incan. But there’s one empire that was once the largest contiguous empire in history, putting all others to shame.

We’ve all heard of the pervasive influence of American culture, from Hollywood to big clothing brands. And some of us have heard that some American holiday traditions have crossed over into other cultures of the world, like Halloween candy and love notes on Valentine’s Day. But did you know that there is one American holiday that is celebrated in an official manner by three other countries?