At the Perryville Community Park in Perryville, in the US state of Maryland, not far from the Perry Point Veteran's Medical Center, is a group of about a hundred trees with cryptic messages carved into their barks. The trees sit on land that was once part of the Perry Point Veteran’s Administration Medical Center before becoming the Perryville Park. The Medical Center is a psychiatric hospital, and many of its patients are U.S. military veterans. During their stay at the psychiatric hospital and rehabilitation center, some of the patients visited the grounds and left their mark for modern-day explorers to discover.

Photo credit: Patch.com