By Brad Segall

VALLEY FORGE, Pa. (CBS) — Valley Forge National Park will celebrate the Fourth of July on Thursday by displaying a true copy of the Declaration of Independence, one of only two known to exist.

The exhibit will allow the public to view the Declaration as it might have looked in July of 1776, and since the original is basically unreadable, noted local historian Tom Lingenfelter says this is the next best thing.

“It’s basically like a photocopy of the original,” he says.

Lingenfelter picked up the document at a Bucks County flea market about 20 years ago. He thought it was a souvenir copy, but after some digging learned of its historical significance.

“It’s the Birth Certificate of America,” Lingenfelter says, “and it’s on America’s birthday, July Fourth. It can’t be much more significant, and a lot of people believe it’s probably the most important document in the world because it changed the whole world.”

He says this document was created in the 1840s with a new process known as anastatic printing.

Lingenfelter says the only other known copy is at Independence National Park in Philadelphia, but it’s not on display. His copy will be at Valley Forge between 10 a.m. and 4 p.m. on the Fourth.

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