The Penny Black is the oldest postage stamp in existence. It was issued in 1840 in Great Britain and featured Queen Victoria.

The USPS handles about 400 million pieces of mail every single day.

There are 42,000 post offices in the United States—more than Starbucks and McDonald’s combined.

There’s a post office on Mt. Fuji in Japan and even one on Mt. Everest in Nepal for mountain climbers.

Millions of letters to Santa are sent out every year, with France and Canada being among the most common countries to participate.

At one time, people were actually able to mail living children, including babies, because it was cheaper than buying a train ticket. They traveled with the postman, not in a box.

There’s even a post office for the very few people who live in Antarctica.

The USPS once used mule trains to deliver mail to the Grand Canyon.

The USPS started using ZIP codes in 1963.

Some mail gets lost, but occasionally letters are found and delivered—even a century later.

The USPS is the largest employer of veterans in the United States.

In some countries, people can address mail with terms like “Grandma” or “Grandpa,” and if the local postman knows the area well, it will still be delivered.

There’s a post office in a tree that has been operating for many decades in Kenya.

Victory Mail was used during World War II, where letters were photographed, miniaturized, and reprinted to save costs.

Ochopee, Florida, has the smallest post office in the country at just 61 square feet.

Cyrus the Great of Persia established one of the earliest known postal systems around 550 BCE.

Australia used camel trains to deliver mail in the 19th century.

In Iceland, people can draw maps on envelopes instead of writing a traditional address, and the mail will still be delivered.

Due to the Geneva Conventions, prisoners of war in some countries receive free postage services.

All United States presidents receive free postage for the rest of their lives, a benefit known as “franking privilege.”

People once sent bricks and stones through the mail because it was cheaper than using freight services.

The British Guiana 1c Magenta is the most expensive stamp in the world, valued at $8.3 million.

The longest mail route in the U.S. is 187 miles long, located in rural Alaska.

The USPS once allowed people to mail livestock and pets, and the Soviet Union had a similar system.

The most valuable stamps for collectors are often those that were misprinted during production.