The lost historical treasure that singlehandedly made the U.S. Air Force possible has finally been tracked down.

The 110-year-old patent file for Orville and Wilbur Wright’s ‘Flying Machine’ vanished 36 years ago from the National Archives treasure vault. The Wright Brothers’ patent, which contains the original blueprint of the world’s first functional airplane, disappeared in 1980 while it was on loan to the Smithsonian Museum. Record keepers did not notice the patent’s absence until 2000.

The document represents the beginning of American aviation at we know it. Filed in 1903, the Wright Brothers patented their flying machine a full nine months before it had even completed its first flight. That flight lasted 12 seconds and covered 120 feet.

“Be it known that we Orville Wright and Wilbur Wright, both citizens of the United States, residing in the city of Dayton and state of Ohio, have jointly invented a new and useful machine for navigating the air,” the patent reads.

So what happened to this relic? Where has it been for 36 years?

In the purest example of government disorganization, the blueprint hadn’t been stolen or lost at all. It had just been archived in the wrong place.

Volunteer archivist Bob Beebe stumbled upon the document in a 15-foot stack of old papers in a ‘storage cave’ in Kansas. Archivists concluded that after it was loaned to the Smithsonian, the Wright Brothers’ patent was misfiled.

Other documents currently missing from the National Archives include Eli Whitney’s patent for the cotton gin, personal letters from Abraham Lincoln and photographs from the moon landing.

[International Business Times]