Those who've seen it say it's a bright white light, glowing deep in side the woods, changing size and shape before fading into the darkness.

For half a century, the Paulding Light has been a legend in the Upper Peninsula, but it's not easy to find.  You have to take narrow U.S. -45 to Paulding, which is a tiny speck of a town near the Wisconsin border.

Then turn down unmarked Robbins Pond Road, also known as the remnant of old U.S. -45.  About a half mile in, it dead ends at a guardrail overlooking a tree filled valley where the former highway vanishes into the woods.

The first recorded sighting of the Paulding Light was in 1966 when a group of high school boys reportedly saw it and told the local sheriff.

Others have speculated that it's swamp gas.  Or something related to the Northern Lights.  Maybe even something extraterrestrial.  Here's more from the Detroit Free Press.