5 Cool Secret Codes Hiding In Plain Sight Around The World

#5. USB Dead Drops Hide A Secret Information Network

"Dead dropping" is a practice wherein tech-savvy hipsters glue USB ports onto public spaces, like walls and bridges, for random people to stumble across and dig into.

#4. Native American Trail Trees Hidden In The Forests

Before GPS technology gently guided us into the ocean instead of our intended destination, Native Americans needed to navigate the wilderness. So they marked their walking trails with saplings, tying them down in such a way that the trunks were forced to grow into specific patterns.

#3. The Giant Concrete Arrows Scattered All Across The U.S

The bad news is that you're probably still going to die. But the good news is that you stumbled on a valuable piece of American history! ... right before you died.

Here's the story: Fewer than 20 years after the Wright Brothers' historic flight, the U.S. Postal Service was already using planes to shorten cross-country mail delivery times from weeks to days. The problem was that, in those early days, pilots had no idea how to navigate in the air. The Postal Service addressed this problem by covering the landscape in giant arrows. At the time, the arrows were painted bright yellow and accompanied by tall beacon towers to facilitate navigation at night.