We unexpectedly stumbled upon Prospect's Fort Knox when we went looking for the Penobscot Narrows Bridge Observatory during a recent getaway Down East. It is a handsome, well-maintained testament to the past, built to thwart an anticipated British invasion that never materialized. Haunted Fort by author Liza Gardner Walsh gives a well-researched and detailed look at the history of the fort in an easy prose that does not sounds like a dry, boring lecture.

A great many photos of the fort are included, from both today and throughout its history, as well as pictures of its soldiers, builders and caretakers. It obviously took some time and effort to research this comprehensive little book. But being an impressive testament to a foregone era is not all the fort has to offer.

Liza Gardner Walsh takes a look at the "other" side of Fort Knox. When employees close up for the night and go home, there is convincing evidence that the fort maybe isn't quite empty.

Fort Knox is well documented as being haunted. Many employees and visitors have had spirit encounters in and around the fort, and some of their stories are included here. The fort is a common destination point for East Coast Ghost Trackers, who regularly run ghost hunts and tours at the site. "Fright at the Fort" is hosted around Halloween, and it's known as the "best Halloween experience in Maine." All proceeds are donated toward the preservation of the fort.

The author brings us with her on both a ghost hunt and a "Fright at the Fort" experience, and it is loads of fun to read about. She also includes some photos of actual apparitions and orbs. The photograph of the Native American woman reflected in the window is especially spooky.

And now for the meat and potatoes. When my husband and I stumbled onto this fort, we had never heard of it and knew nothing about it. It was a gorgeous, sunny and 72-degree day with a light breeze and a few sparse clouds, and we innocently thought it was perfect for taking a nice romp around the grounds. Little did we know. When entering a powder magazine that had just been opened to the public, my husband was just raising his camera to shoot the old door leading into it, when a white, golf ball-sized orb streaked from the left side of his vision to the right, disappearing into the wall next to the door. Right in front of his face, at about an arm's length. He was quite excited, yelling, "Did you see that? Did you see that?" (I didn't.) We wondered to ourselves, "I wonder if they know they've got spirits here?" When we finally made our way to the gift shop, we found this book. As a result, we started examining the pictures we took, and sure enough, we got a ghost. At the very end of one of the alleys, when the pic on the cell phone is enlarged as much as possible, is a fully materialized apparition, complete with a head, arms, upper torso and beard. There was nothing and no one in the tunnel but us at the time. I'm going to forward the photo to East Coast Ghost Trackers, and I hope they will concur that it's the real deal.

The Friends of Fort Knox lovingly maintain the grounds and interior of the site. It is immaculate and a pleasure to explore. I highly recommend taking a ride up to Prospect if you're in the area to experience the fort and take in the views at the top of the observatory (they're at the same site). Check out Haunted Fort for some light, entertaining and informative reading before you go.