Holding the small blue paper book embossed with the gold lettering “United States of America” can feel similar to holding the key to adventure. Behind each international door your passport unlocks is a slice of humanity with rich history, delicious food, unique customs, and intriguing people.

While living in central Europe, I’ve observed that most of the nationals seem to have a passport. While the European Union doesn’t require presentation of a passport to cross between countries that are part of the border-free Schengen area, it is of course advantageous to have a passport in case you need to prove your identity—which many countries outside of Europe do require. Cross-country travel is common because driving (or taking the train) between neighboring countries in Europe often takes less time than it does between neighboring states in the U.S.

As an American, the passport can sometimes fall off the radar likely because you don’t need one to prove identity (a state-issued license will do) or to travel across state lines. According to 2014 State Department statistics, the majority of Americans do not have a passport. In fact, about 46 percent of Americans have a valid passport, according to the 2014 stats. Considering these figures, here are five reasons why you might consider getting a passport.

1. Element of surprise

Often, opportunity doesn’t plan ahead. Opportunity rings your doorbell then runs away. Once in a great while, opportunity offers you an unexpected reason to travel. Maybe you win a magazine’s Pinterest contest and get to hop on a plane to Thailand next month. Perhaps your college roommate is having his wedding in Brazil (perhaps he traveled abroad and never left). A date might invite you to a fancy, black-tie ball at the Imperial Palace in Vienna (hand raised on this one, it can happen). Believe me, you will want to be there for the experience and a ready passport is just another green light on the travel checklist.

2. Stamp of promotion

Image this. You’re killing it at your job and your performance has caught the eye of your boss. Congrats, you are going to represent the company at the industry conference in Japan. Oh, and the conference is next week. You’ll want that blank passport page available.

Owning a passport is a part of living the life of a 21st century professional. Whether you work for a startup headquartered in India or design for a clothing line with a market in Denmark, the world of international business demands the availability of physical presence when telecommunication just doesn't cut it.

3. Self-growth

Travel takes the art of self-study and exploration to another level. Traveling to a new country and throwing yourself into the language and customs can reveal unexpected challenges that help you grow. How does one read a train map when it’s in Czech? How do you get back to your Airbnb from here? Wait, how do you order a glass of wine?

With international travel you gain a certain education that cannot be found in a classroom; it’s a lesson in communication and logic that you can use in your job and relationships back home. Plus, you can experience how different policies, governments and political systems work in other countries.

4. Alternate form of identification

At some point you are going to need a secondary form of photo identification, even stateside. So, when the U.S. Department of Transportation demands another form of identification then you will have your passport ready to prove your existence.

5. Stamp of approval

Your passport will grant you access to experiences and memories that can never be taken away. These moments captured in Technicolor and held in your soul will run deeper than that Instagram pic that failed to captured the vibrancy of a Santorini sunset. And that is what makes your passport invaluable.