Manhattan Project Trinity

On This Day - August 13th

August 13th may seem just like any other summer date, but there’s more to today than meets the eye. If you're not already celebrating a special occasion today, we’ve rounded up some of the most interesting facts and figures about August 13th that you’re going to want to keep in mind for the years to come. Let’s get started…

On this day

Fun Facts about Mexico

The world saw the end of the Aztec Empire.

In 1521, Spanish conquistadors, under the orders of Hernán Cortés, captured the Aztec Emperor Cuauhtémoc during his domicile in Tenochtitlan. In so doing, this marked the end of the Aztec Empire.

Enryaku-ji Temple

The Tenbun Hokke Disturbance took place.

In 1536, Buddhist monks from the Enryaku-ji Temple in Kyōto set fire to 21 Nichiren temples! This took place during what became known many years later, among historians, as the Tenbun Hokke Disturbance.

Mars south polar caps

An astronomer made an important discovery!

In 1642, Dutch astronomer Christiaan Huygens made history that impacted the way we saw the skies forever. He discovered Mars’ southern polar cap – and centuries later, we’re still learning all sorts of new things about the red planet. Hopefully we’ll get there some day!

Facts about China

The Battle of Shanghai took place.

In 1937, during the second of the Sino-Japanese Wars, Japanese armed forces began the Battle of Shanghai. The battle ended up lasting three months and involved one million troops!

Manhattan Project

The Manhattan Project started.

In 1942, the Manhattan Project began under US General Leslie Groves. This controversial project was pivotal to the development of the atomic bomb – which was later used to bomb Hiroshima and Nagasaki in Japan toward the end of World War II.

Special Days Falling on August 13th

August 13th is just as much a date to celebrate as it is one to look back on. So, today, consider some of the best international holidays that take place on August 13th!
Obon Festival dancers

Obon Festival

Every year, from the 13th to the 15th of the seventh lunar month, the Obon Festival takes place in Japan. The holiday celebrates the spirits of the dead ancestors of the people in Japan. They see it as an opportunity to rekindle the connections between them and their lost loved ones. As spooky as it may sound, it is a festival filled with dancing, music, and all kinds of fun activities! There are also incredible traditional dishes, the traditional cleaning of the graves of the ancestors, and the lighting of chochin lanterns. It truly is an incredible festival to see!

flag of Tunisia

Tunisian Women’s and Family Day

Every August 13th in Tunisia is the premier date to celebrate women and family. The day honors the women of the world who keep our societies running, who continue to fight for careers, equal opportunities, and more. It's also an important date to honor the families these women care for – and everything they are. The date has been celebrated since 2017, and long may it continue!

Left Handed People Facts

International Left-handers Day

Did you know that there are at least three US Presidents who were left-handed? That’s Barack Obama, Bill Clinton, and Ronald Reagan – and today’s a great day to learn more about how left-handers see (and handle) the world if you’re a right-handed person. Despite the fact there are millions of left-handed people all over the globe, there are still some accessibility demands that just aren’t being met. Why not try writing with your left hand, at least, to mark the occasion?

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This page was last modified on August 7, 2023. Suggest an edit

This month in history

Smokey Bear made his debut! Only you can prevent forest fires – at least, that’s what the world’s most famous fire safety bear had to tell us from August 1944 onward. Without Smokey, a generation of kids may not have known how to take caution around wildfires across North America – and given that wildfires are still causing major problems all over the globe, any advice is still very welcome!

Famous Birthdays on August 13th

Jay Buhner, American MLB player, born 1964

Fidel Castro, Cuban revolutionary, born 1926

Alfred Hitchcock, British film director, born 1899

Annie Oakley, American sharp shooter, born 1860

George Stokes, Irish physicist and mathematician, born 1819

Fun Facts about the Leo Star Sign

If you were born on August 13th…


…you’re a Leo! You are confidence itself! You command every room you walk into, and you love the attention!


Learn more about Leos from our complete fact file on this purr-fect star sign.

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